Reference Type: Journal Article Author: Acef, O.; Borde, C. J.; Clairon, A.; Pierre, G.; Sartakov, B. Year: 2000 Title: New accurate fit of an extended set of saturation data for the v3 band of SF6: Comparison of Hamiltonians in the spherical and cubic tensor formalisms Journal: Journal of Molecular Spectroscopy Volume: 199 Issue: 2 Pages: 188-204 Keywords: molecular spectroscopy; spherical top molecules; saturation spectroscopy Abstract: An extended set of 321 frequencies of vibration-rotation lines of the v3 band of SF6 has been measured by saturation spectroscopy using various isotopic species of CO2. A least-squares fit of these data has been performed using an effective Hamiltonian written either with a spherical tensor or with a cubic tensor formalism. We have derived correspondence formulas between the parameters in the two approaches and checked that both formalisms give the same results up to the seventh order. Corrected parameters are given for the fit with a fifth-order Hamiltonian. An accurate representation of the band is obtained at the tenth order (standard deviation approximate to 12 kHz) with a remarkable predictive power (better than 40 kHz) for J values less than or equal to 100. The convergence properties of the Hamiltonian power expansion are discussed, (C) 2000 Academic Press.
Reference Type: Journal Article Author: Asselin, P.; Soulard, P.; Manceron, L.; Boudon, V.; Pierre, G. Year: 2000 Title: High resolution Fourier transform infrared spectroscopy and analysis of the v6 band of jet-cooled Mo(CO)6 Journal: Journal of Molecular Structure Volume: 517 Pages: 145-155 Keywords: molybdenum hexacarbonyl; FTIR spectroscopy; molecular beam; octahedral splitting Abstract: Rovibrational FTIR spectra of Mo(CO)6 have been recorded in supersonic argon expansions at 0.004 cm-1 resolution. Rotational constants have been determined for the v6 fundamental band of Mo(12CO)6 and for the parallel band of the symmetric top isotopomer Mo(13CO)(12CO)5. From these results, a precise estimate of the Coriolis parameter for the v6 band of the main isotopomer Mo(12CO)6 is derived, necessary for the analysis of the v6 spectrum. The observation of an octahedral splitting clearly resolved for the highest J-lines in the R branch prompted the use of a specific treatment based on the tensorial formalism developed by J.P. Champion, M. Loete, G. Pierre (Spherical top spectra, in: K.N. Rao, A. Weber (Eds.), Spectroscopy of the Earth's Atmosphere and Interstellar Medium, Academic Press Inc., New York, 1992, pp. 339-422). (C) 2000 Elsevier Science B.V. All rights reserved.
Reference Type: Journal Article Author: Bermejo, D.; Martinez, R. Z.; Loubignac, E.; Boudon, V.; Pierre, G. Year: 2000 Title: Simultaneous analysis of the v2 Raman and v2+v6 infrared spectra of the SF6 molecule Journal: Journal of Molecular Spectroscopy Volume: 201 Issue: 1 Pages: 164-171 Keywords: molecular spectroscopy; Raman ; spherical top Abstract: High-resolution Raman spectra of the v2, band of SF6, have been recorded at a temperature of 195 K (dry ice) and a pressure of 39 mbar. These spectra were analyzed using a new set of programs specially written for XY6, molecules. These programs, called HTDS (highly spherical top data system) in reference to the set of programs called STDS (spherical top data system written for XY4, molecules) can be freely accessible through ftp (user anonymous) at jupiter.u-bourgogne.fr or on the web at the URL http://www.u-bourgogne.fr/LPUB/shTDS.html The study of v2, was made using a Hamiltonian developed through the third order. Four parameters were determined. The standard deviation obtained using about 559 data up to J < 61 is 0.0021 cm-1. This result is used to refine by simultaneous analysis the v2 and v2+v6 bands of SF6. This new fit allows the determination for the first time of some v6 parameters. The values obtained for this band (forbidden in Raman and in infrared) will be used to study the infrared hot bands in the v3 and v4 regions. (C) 2000 Academic Press.
Reference Type: Journal Article Author: Dhont, G.; Sadovskii, D.; Zhilinskii, B.; Boudon, V. Year: 2000 Title: Analysis of the "unusual" vibrational components of triply degenerate vibrational mode v6 of Mo(CO)6 based on the classical interpretation of the effective rotation-vibration Hamiltonian Journal: Journal of Molecular Spectroscopy Volume: 201 Issue: 1 Pages: 95-108 Keywords: rovibrational interactions; spherical top molecules; quantum classical correspondence Abstract: Relational structure of the triply degenerate vibrational state v6(F1u) of the octahedral molecule Mo(CO)6 is analyzed qualitatively on the basis of classical mechanics. We show that the energy level redistribution between the vibrational components of v6(F1u) occurs due to rotational excitation and is related to the formation of singular points of classical rotational energy surfaces, The singularity is stable under small variations of parameters of the effective rovibrational Hamiltonian. Parameters responsible for the persistence of this phenomenon are specified, Comparison with quantum calculations demonstrates the high qualitative and quantitative accuracy of our classical analysis, (C) 2000 Academic Press.
Reference Type: Journal Article Author: Dupont, J. M.; Deroussiaux, A.; Coquard, M. P.; Lavorel, B.; Faucher, O.; Loete, M.; Jauslin, H. R. Year: 2000 Title: Dynamical stark effect in the v2/v4 vibrational polyad of SiH4: Theory and observation Journal: Journal of Molecular Spectroscopy Volume: 199 Issue: 2 Pages: 252-258 Abstract: We report a theoretical and experimental investigation of the dynamical Stark effect in a tetrahedral molecule, silane (SiH4). We use a tetrahedral formalism and Floquet theory to calculate the absorption spectra for the molecule dressed by an intense nonresonant pulsed laser. Experimentally, the dynamical Stark effect is observed fur transitions of the v2/v4, vibrational polyad of SIH4, by means of nanosecond diode laser absorption spectroscopy and a Nd:YAG laser excitation. (C) 2000 Academic Press.
Reference Type: Journal Article Author: Fejard, L.; Champion, J. P.; Jouvard, J. M.; Brown, L. R.; Pine, A. S. Year: 2000 Title: The intensities of methane in the 3-5 mm region revisited Journal: Journal of Molecular Spectroscopy Volume: 201 Issue: 1 Pages: 83-94 Keywords: methane ; high resolution; infrared ; absolute intensities Abstract: The analysis of the linestrengths of the infrared spectrum of methane (12 and 13) in the 3-5 mm region has been revisited on the basis of new measurements from Fourier transform spectra recorded at Kitt Peak under various optical densities. A simultaneous fit of these new data with previously reported tunable difference-frequency laser data has been done. An effective transition moment model in tensorial form up to the third order of approximation within the Pentad scheme has been used. The standard deviations achieved are very close to the experimental precision: 3 and 1.5%, respectively, for the two sets of data for the 12CH4 molecule, representing a substantial improvement with respect to earlier studies. The integrated bandstrengths obtained in the present work differ from previously reported values by factors ranging from -5 to +6%. The correction for the v3, band, the strongest band of the Pentad system, is +2% with respect to the study of Hilico et al. [J. C. Hilico, J. P. Champion, S. Toumi, V. G, Tyuterev, and S. A. Tashkun, J. Mot Spectrosc. 168, 455-476 (1994)]. (C) 2000 Academic Press.
Reference Type: Journal Article Author: Hussong, J.; Stricker, W.; Bruet, X.; Joubert, P.; Bonamy, J.; Robert, D.; Michaut, X.; Gabard, T.; Berger, H. Year: 2000 Title: Hydrogen CARS thermometry in H2-N2 mixtures at high pressure and medium temperatures: influence of linewidths models Journal: Applied Physics B Lasers and Optics Volume: 70 Issue: 3 Pages: 447-454 Abstract: In order to improve the accuracy of H2 CARS thermometry, H2Q-branch CARS spectra have been recorded for various H2-N2 mixtures in a high-pressure cell at different pressures and temperatures (up to 40 bar and 875 K). Due to the low spectral resolution of broadband CARS experiments, the relevant spectral lineshape factor is the linewidth ratio G(Q(3))/G(Q(1)), since Q(1) and Q(3) are the most intense lines of the Q-branch spectrum in this temperature range. For the first time, the speed-inhomogeneous effects are accounted for in the simulation of the CARS profiles. The evaluated temperatures are in good agreement with reference Values obtained by thermocouples. The specific role on the accuracy of H2 CARS thermometry of the speed inhomogeneity is carefully analyzed, in connection with the influence of the nitrogen concentration.
Reference Type: Journal Article Author: Nikitin, A.; Champion, J. P.; Tyuterev, V. G.; Brown, L. R.; Mellau, G.; Lock, M. Year: 2000 Title: The infrared spectrum of CH3D between 900 and 3200 cm-1: extended assignment and modeling Journal: Journal of Molecular Structure Volume: 517 Pages: 1-24 Keywords: infrared ; methane ; high resolution; polyad Abstract: The high resolution infrared spectrum of CH3D in the region from 900 to 3200 cm-1 has been analyzed on the basis of Fourier transform spectra recorded at Kitt Peak and at Giessen, A theoretical model for an effective hamiltonian in terms of irreducible tensor operators recently adapted to symmetric top molecules has been used in order to consider simultaneously all available transitions between the lowest three polyads of the molecule: the Ground State (G.S.), the Triad (three interacting fundamental bands in the 8 mm region) and the Nonad (nine interacting bands in the 4 mm region). A preliminary simultaneous fit of 3467 Triad-G.S., 5208 Nonad-G.S., and 2487 Nonad-Triad (bot band) transition wavenumbers has been done. The standard deviations achieved were 2.1, 4.7 and 4.3 x 10-3 cm-1, respectively. A preliminary analysis of the transition intensities was also undertaken at a level of precision of the order of 5% or better. (C) 2000 Elsevier Science B.V. All rights reserved.
Reference Type: Journal Article Author: Pieroni, D.; Nguyen Van, Thanh; Brodbeck, C.; Hartmann, J. M.; Gabard, T.; Champion, J. P.; Bermejo, D.; Domenech, J. L.; Claveau, C.; Valentin, A. Year: 2000 Title: Experimental and theoretical study of line mixing in methane spectra. IV. Influence of the temperature and of the band Journal: Journal of Chemical Physics Volume: 113 Issue: 14 Pages: 5776-5783 Abstract: Line-mixing effects are studied in infrared bands of CH4 perturbed by N2 at various pressures. The effects of temperature are investigated in the nu(3) region whereas spectral shapes of the v2, v4, and v3 bands are compared at room temperature. The theoretical approach proposed in preceding papers is used in order to model and analyze the influence of collisions on the spectral shape. All model parameters are now fixed to values determined in the previous studies. Comparisons between measurements and spectra computed with and without the inclusion of line mixing are made. They show that our approach satisfactorily accounts for the effects of temperature, pressure, and of rotational quantum numbers on the absorption by the v3 band. Furthermore, the effects of collisions on spectra in the v4 region at room temperature are also correctly calculated. On the other hand, the proposed approach fails in modeling the evolution with increasing pressure of absorption in the spectral range containing the v2 band. This result is attributed to the Coriolis coupling between the v2 and v4 vibrational states and to a contribution whose physical origin remains unclear. The latter, which is negligible when CH4-He mixtures are considered, behaves as collision-induced absorption. (C) 2000 American Institute of Physics. [S0021-9606(00)00736-4].
Reference Type: Journal Article Author: Pieroni, D.; Hartmann, J. M.; Chaussard, F.; Michaut, X.; Gabard, T.; Saint Loup, R.; Berger, H.; Champion, J. P. Year: 2000 Title: Experimental and theoretical study of line mixing in methane spectra. III. The Q branch of the Raman v1 band Journal: Journal of Chemical Physics Volume: 112 Issue: 3 Pages: 1335-1343 Abstract: The shape of the v1 Raman Q branch of CH4 perturbed by Ar and He at room temperature has been studied. Stimulated Raman spectroscopy (SRS) experiments have been made in the 2915-2918 cm-1 spectral region for total pressures from 0.4 to 70 atm and mixtures of approximate to 5% CH4 with He and Ar. Analysis of the spectra demonstrates that the shape of the Q branch is significantly influenced by line mixing and much narrower than what is predicted by the addition of individual line profiles. For the first time, a model is proposed for the calculation and analysis of the effects of collisions on the considered spectra. In this approach, the rotational part of the relaxation matrix is constructed, with no adjustable parameter, starting from semiclassical state-to-state rates. Two empirical constants which account for the shift and broadening of the branch due to vibrational effects are introduced and their values are determined from fits of measured spectra. Comparisons between measurements and results computed with and without the inclusion of line mixing are made. Although not perfect, our model satisfactory accounts for most effects of pressure at low densities, where rotational transfers are dominant, as well as at high densities, where the profile is strongly influenced by vibrational contributions. It is shown that collisions with He and Ar lead to different behaviors at elevated pressure. The influence of the perturbation introduced by the Fermi coupling between the v1 and v2+v4 levels is discussed and the rotational and vibrational contributions to the spectral shape are pointed out. (C) 2000 American Institute of Physics. [S0021-9606(00)02103-6].
Reference Type: Journal Article Author: Pine, A. S.; Gabard, T. Year: 2000 Title: Speed-dependent broadening and line mixing in CH4 perturbed by Ar and N2 from multispectrum fits Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 66 Issue: 1 Pages: 69-92 Abstract: Speed-dependent broadenings and shifts have been determined for the P and R branches of the v3 band of CH4 perturbed by Ar and N2 using a multispectrum fitting analysis of high-resolution tunable difference-frequency laser spectra recorded at pressures less than or equal to 67 kPa. For J greater than or equal to 3, the tetrahedral fine structure components in each J manifold are collisionally coupled and exhibit significant interference. The coupled lines are treated using a speed-dependent first-order line-mixing profile and are compared to a speed-independent full relaxation matrix inversion procedure with off-diagonal coupling elements calculated from an atom-atom Lennard-Jones potential model, (C) 2000 Elsevier Science Ltd. All rights reserved.
Reference Type: Journal Article Author: Rey, M.; Boudon, V.; Loete, M.; Michelot, F. Year: 2000 Title: A tensorial formalism adapted to the rovibronic couplings in the colored hexafluorides: Application to the v5(F2g) and v3(F1u) modes Journal: Journal of Molecular Spectroscopy Volume: 204 Issue: 1 Pages: 106-119 Keywords: tensorial formalism; colored hexafluorides; Jahn Teller effect; rovibronic couplings Abstract: A tensorial formalism adapted to the case of transition-metal hexafluorides in a degenerate electronic state has been developed on the basis of preceding works about spherical-top molecules in a nondegenerate electronic state. We have introduced electronic operators constructed using group theory features and some physical considerations. Vibronic couplings (Jahn-Teller effect, etc.) have been reviewed for the triply degenerate vibrational modes v5(F2g) and v3(F1u) leading to the identification of the main vibronic parameters. For the first time, an effective rovibronic Hamiltonian as well as the effective transition moment operators (dipole moment and polarizability) for rovibronic transitions have been studied qualitatively thanks to the tensorial algebra properties. (C) 2000 Academic Press.
Reference Type: Journal Article Author: Rotger, M.; Boudon, V.; Loete, M. Year: 2000 Title: Spectroscopy of XY5Z (C4v) molecules: A tensorial formalism adapted to the O(3) OhC4v chain Journal: Journal of Molecular Spectroscopy Volume: 200 Issue: 1 Pages: 123-130 Keywords: tensorial formalism; XY5Z symmetric tops Abstract: A tensorial formalism adapted to the case of XY5Z symmetric tops has been developed as an extension of the usual one for the octahedral molecules. We use the O(3) OhC4v group chain. All the coupling coefficients and formulas for the computation of matrix elements are given for this chain. Such relations are also deduced in the C4v group itself. (C) 2000 Academic Press.
Reference Type: Journal Article Author: Rotger, M.; Boudon, V.; Loete, M. Year: 2000 Title: Spectroscopy of XY5Z (C4v) molecules: Development of the Hamiltonian and the transition moment operators using a tensorial formalism Journal: Journal of Molecular Spectroscopy Volume: 200 Issue: 1 Pages: 131-137 Keywords: tensorial formalism; XY5Z symmetric tops; Hamiltonian ; dipole moment; polarizability Abstract: We present a development of the Hamiltonian, dipole moment, and polarizability operators of XY5Z (C4v) molecules using a tensorial formalism derived from the one developed previously in Dijon for XY6 molecules. These operators are involved in the calculation of the energies and intensities of rovibrational transitions and are essential for spectrum simulations. Expressions for the matrix elements are derived for all these operators. (C) 2000 Academic Press.
Reference Type: Journal Article Author: Wenger, C.; Boudon, V.; Champion, J. P.; Pierre, G. Year: 2000 Title: Highly-spherical Top Data System (HTDS) software for spectrum simulation of octahedral XY6 molecules Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 66 Issue: 1 Pages: 1-16 Keywords: octahedral molecules; tensorial formalism; vibrational extrapolation Abstract: The Spherical Top Data System (STDS) program suite developed in Dijon has been extended into two directions. First, the vibrational extrapolation is now possible for any kind of polyad scheme, this one being fully specified in the input parameters of the programs for hamiltonian and transition moment model calculations. This was not the case of the preceding version which was based on the polyad scheme of methane. Secondly, it is now possible to study any band and polyad of XY6 molecule for which a complete treatment in the Oh group is made. Up to now, only some vibrational levels of these molecules (F1u levels in particular) could be studied using equivalences with the Td group. Some examples mainly concerning the SF6 molecule are presented. As before, this suite is composed of a series of FORTRAN programs called by a UNIX script. The whole package is freely accessible through ftp (user anonymous) at jupiter.u-bougogne.fr. (C) 2000 Elsevier Science Ltd. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; Pierre, G.; Burger, H. Year: 2001 Title: High-resolution spectroscopy and analysis of the v4 bending region of SF6 near 615 cm-1 Journal: Journal of Molecular Spectroscopy Volume: 205 Issue: 2 Pages: 304-311 Abstract: The high-resolution Fourier transform spectrum of the v4 bending region of SF6 near 615 cm-1 has been recorded at 213 K. We were able to perform a simultaneous analysis of the v4 and v4 + v6 - v6 bands of the main isotopomer, namely 32SF6. This is the first detailed analysis of a hot band for this molecule. The v4 band of 34SF6 was also analyzed and the Q branch of the v4 band of 33SF6 was identified. In both cases we used the HTDS software developed in Dijon. (C) 2001 Academic Press.
Reference Type: Journal Article Author: Boudon, V.; Burger, H.; Mkadmi, E. B. Year: 2001 Title: High-resolution spectroscopy and analysis of the v3 and v4 fundamentals of monoisotopic 70GeF4 Journal: Journal of Molecular Spectroscopy Volume: 206 Issue: 2 Pages: 172-180 Abstract: The first high-resolution study on germanium tetrafluoride is reported. We used a monoisotopic sample of 70GeF4. The FTIR spectra of the two infrared active fundamentals, namely the v4 (bending) and v3 (stretching) modes, were recorded at a temperature of ca. 210 K and a resolution (1/maximum optical path difference) of 0.0031 and 0.0023 cm-1, respectively. These spectra were analyzed using the STDS software developed in Dijon. In both cases, we obtained a fit with a root mean square better than 1 x 10-3 cm-1. Both bands show very regular structures with no detectable perturbation. (C) 2001 Academic Press.
Reference Type: Journal Article Author: Grigoriev, I. M.; Filippov, N. N.; Tonkov, M. V.; Gabard, T.; Le Doucen, R. Year: 2001 Title: Estimation of line parameters under line mixing effects: the v3 band of CH4 in helium Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 69 Issue: 2 Pages: 189-204 Abstract: Spectra of CH4-He mixtures were measured in the P and R branch regions of v3 vibration-rotation band at lower pressures of 0.26-1.0 bar and for the whole band at higher pressures up to 90 bar. The line broadening coefficients were found from lower pressure data for the lines of the P branch. These coefficients were calculated in the framework of the Robert and Bonamy semi-classical approach. In general, they agree with the experimental ones, but a small J-dependent deviation was observed. Line mixing effects were observed at all pressures. At higher pressures they were interpreted in terms of the adjusted branch-coupling model. At lower pressures line mixing effects were found to be especially pronounced in the region of the relatively weak lines forming the clusters from R(16) to R(19). (C) 2001 Published by Elsevier Science Ltd.
Reference Type: Journal Article Author: Rotger, M.; Boudon, V; Burger, H.; Willner, H. Year: 2001 Title: High-resolution spectroscopy and analysis of the v4 band of 80SeF6 Journal: Chemical Physics Letters Volume: 339 Issue: 1-2 Pages: 83-88 Abstract: The Fourier-transform spectrum of the v4 bending region of 80SeF6 around 435 cm-1 has been recorded at a temperature of 217 K with a resolution of 2.3 x 10(-3) cm-1. This fundamental has been analyzed using the set of programs called highly spherical top data system (HTDS). Altogether 958 transitions were assigned and fitted with an rms of 0.0003 cm-1. The effective Hamiltonian was developed up to the fourth order. Parameters and simulations are presented. The v4 band center is located at 435.099 cm-1. (C) 2001 Elsevier Science B.V. All rights reserved.
Reference Type: Journal Article Author: Hilico, J. C.; Robert, O.; Loete, M.; Toumi, S.; Pine, A. S.; Brown, L. R. Year: 2001 Title: Analysis of the interacting octad system of 12CH4 Journal: Journal of Molecular Spectroscopy Volume: 208 Issue: 1 Pages: 1-13 Abstract: The octad system of methane 12CH4 has been analyzed with a fourth-order (459 parameters) Hamiltonian for energy levels and a third-order (28 parameters) dipole moment expansion for infrared intensities. Nearly 8000 assigned positions and 2500 measured line intensities (obtained with the Fourier transform spectrometer located at Kitt Peak National Observatory/National Solar Observatory) have been considered in the modeling. Infrared (Octad-Ground State) and hot bands (Octad-Dyad) data have been used, While the model does not reproduce the measurements at their inherent experimental precisions, it has been sufficient to interpret and substantially assign this spectral region of methane for the first time in over 30 years of investigation, (C) 2001 Academic Press.
Reference Type: Journal Article Author: Rey, M.; Boudon, V.; Loete, M.; Asselin, P.; Soulard, P.; Manceron, L. Year: 2001 Title: The spectrum of an octahedral molecule in a degenerate electronic state : The v6 fundamental band of jet-cooled V(CO)6 Journal: Journal of Chemical Physics Volume: 114 Issue: 24 Pages: 10773-10779 Abstract: The jet-cooled FTIR spectrum of the v6 fundamental band (C-O stretch) of vanadium hexacarbonyl, V(CO)6, is studied for the first time. The spectrum shows a very unusual structure consisting of three well-defined broad subbands, without the usual PQR structure. V(CO)6 being an open-shell system this is attributed to a dynamical F2gxF1u Jahn-Teller coupling which considerably complicates the analysis. A new theoretical model based on group theory and tensorial algebraic techniques is developed in this paper for the very first attempt to analyze such a rovibronic spectrum. The assumption of a negligible spin-orbit coupling is validated by the overall agreement between predicted and observed band profiles. The rovibronic Hamiltonian and dipole moment operators have been expanded in order to enable a simultaneous treatment of the four vibronic sublevels. We were able to satisfactorily reproduce the band profile and thus to give the first estimation of some rovibronic parameters for this molecule. (C) 2001 American Institute of Physics.
Reference Type: Journal Article Author: Rotger, M.; Decrette, A.; Boudon, V.; Loete, M.; Sander, S.; Willner, H. Year: 2001 Title: High-resolution spectroscopy and preliminary analysis of the v1/v8 dyad of SF535Cl Journal: Journal of Molecular Spectroscopy Volume: 208 Issue: 2 Pages: 169-179 Abstract: The Fourier transform infrared spectrum of monoisotopic SF535Cl has been recorded in the 650- to 960-cm-1 region at a temperature of 203 K, a pressure of 0.2 mbar, and an instrumental bandwidth of 0.002 cm-1. The v1/v8 dyad near 900 cm-1 has been analyzed with an effective Hamiltonian developed up to the fourth order and the help of a recently developed set of programs called C4vTDS (C4v nu Top Data System, http://www.u-bourgogne.fr/LPUB/c4vTDS.html); 1346 transitions for v1, 351 transitions for v8, and 406 ground state combination differences have been assigned and fitted. A global fit has been obtained with an rms of 0.00082 cm-1 for the v1 (a1) band, of 0,0011 cm-1 for the v8(e) band, and of 0.00064 cm-1 for the ground state. (C) 2001 Academic Press.
Reference Type: Journal Article Author: Robert, O.; Hilico, J. C.; Loete, M.; Champion, J. P.; Brown, L. R. Year: 2001 Title: First assignment and line strengths of the 4 v4 band of 12CH4 near 1.9 microns Journal: Journal of Molecular Spectroscopy Volume: 209 Issue: 1 Pages: 14-23 Abstract: The investigation of the methane spectrum in the region 1.6-2 microns has provided the first assignment and analysis of the 4v4 band near 1.9 microns. Hamiltonian and dipole moment operators written in tetrahedral formalism and adapted to the extrapolation method have been used to fit the spectra recorded at the Kitt Peak National Observatory/National Solar Observatory. Nearly 190 line positions and 160 measured intensities have been modeled with standard deviations of 0.107 cm-1 and 18.5% respectively. (C) 2001 Academic Press.
Reference Type: Journal Article Author: Van Hecke C.; Sadovskii, D. A.; Zhilinskii, B. I.; Boudon, V. Year: 2001 Title: Rotational-vibrational relative equilibria and the structure of quantum energy spectrum of the tetrahedral molecule P4 Journal: European Physical Journal D Volume: 17 Issue: 1 Pages: 13-35 Abstract: We find relative equilibria (RE) of the rotating and vibrating tetrahedral molecule P4 and study the correspondence of these RE's to the extremal quantum states in the vibration-rotation multiplet and to the extrema of the semi-quantum rotational energy surfaces obtained for a number of excited vibrational states. To compute the energy of RE's we normalize the full rotation-vibration Hamiltonian H of P4 in the approximation of nonresonant modes v2E and v3F2 and find the stationary points of the resulting normal form (known as reduced effective Hamiltonian Heff) which is defined on the reduced phase space CP2x CP1x S2. Most of these points are fixed points of the symmetry group action on CP2x CP1x S2. To explain our results in more detail we introduce numerical values of the parameters of H, such as the cubic force constants, using an atom-atom harmonic potential with one adjustable parameter. This simple model gives correct qualitative description of the rotational structure of the lowest excited vibrational states v2, v3 and v2 + v3 of P4.
Reference Type: Journal Article Author: Rey, M.; Boudon, V.; Loëte, M. Year: 2001 Title: Tensorial development of the rovibronic hamiltonian and transition moment operators for octahedral molecules Journal: Journal of Molecular Structure Volume: 599 Issue: 1-3 Pages: 125-137 Abstract: We present a development of the Hamiltonian, dipole moment and polarizability operators of octhedral XY6 molecules in a degenerate electronic state. These rovibronic operators are written with the aid of a tensorial formalism derived from the one already used in Dijon in the case of molecules in a non-degenerate electronic state. Electronic operators are defined from the group theory properties. Transition moment operators are introduced in order to consider rovibronic transitions. Spectrum simulations are made thanks to a new version of the HTDS sofware (Ch. Wenger, V. Boudon, J. P. Champion and G. Pierre, J. Quant. Spectrosc. Radiat. Transfer 66 (2000) 16) used for the calculation of rovibrational spectra. Retour à la page SMA / Back to the SMA page
2002
Reference Type: Journal Article Author: Wenger, C.; Rotger, M.; Boudon, V. Year: 2002 Title: C4v Top Data System (C4vTDS) software for infrared spectrum simulation of XY5Z symmetric molecules Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 74 Issue: 5 Pages: 621-636 Abstract: The Highly spherical Top Data System program suite developed in Dijon has been extended in the aim of studying any rovibrational band or polyad of XY5Z (C4v) symmetric top molecules. We work in the O(3) OhC4v chain because most of these species result from the substitution of one ligand of the corresponding spherical tops and thus are relatively close to octahedral symmetry. The choice of this group chain has consequences in the way in which it is used to specify the input parameters of the programs for Hamiltonian and transition moment model calculations. One example concerning the v1/v8 dyad of the SF5Cl35 molecule is presented. As before, this suite consists of a series of FORTRAN programs called as scripts. The whole package is freely accessible through ftp (user anonymous) at jupiter.u-bourgogne.fr or through the World Wide Web at http://www.u-bourgogne.fr/LPUB/c4vTDS.html. (C) 2002 Elsevier Science Ltd. All rights reserved.
Reference Type: Journal Article Author: Grigoriev, I. M.; Filippov, N. N.; Tonkov, M. V.; Champion, J. P.; Gabard, T.; Le Doucen, R. Year: 2002 Title: Line parameters and shapes of high clusters: R branch of the v3 band of CH4 in He mixtures Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 74 Issue: 4 Pages: 431-443 Abstract: The IR absorption spectra of CH4 in pure gas and in mixture with helium were studied in the region of v3 band at higher J line clusters R(17)-R(22). The frequencies and intensities of rotation-vibration lines were estimated from the experimental spectra at Doppler shape conditions. The line frequencies and intensities were calculated and used for the attribution of overlapped lines in clusters. The calculated line intensities are close to the experimental values. The calculated frequency structure of the higher J manifolds are somewhat wider than the observed one. The shapes of helium-broadened line clusters were compared with those calculated accounting for line mixing. The relaxation matrix W, which is necessary in shape calculations, was constructed using semiclassical collision rate constants. The calculated shapes are in satisfactory accordance with the measured ones. (C) 2002 Elsevier Science Ltd. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; Bermejo, D. Year: 2002 Title: First high-resolution Raman spectrum and analysis of the v5 bending fundamental of SF6 Journal: Journal of Molecular Spectroscopy Volume: 213 Issue: 2 Pages: 139-144 Abstract: The high-resolution Raman spectrum of the Q, R, and S branches of the v5 bending fundamental of SF6 has been recorded at a temperature of 195 K (dry ice) and a pressure of 39 mbar. This is the first study ever performed of a v5 band of an XY6 molecule. It has been analyzed thanks to the HTDS software (http://www.u-bourgogne.fr/LPUB/shTDS.html) developed in Dijon. This contribution should be of help in understanding the role hot bands in the strong absorbing v3 region. (C) 2002 Elsevier Science (USA).
Reference Type: Journal Article Author: Boudon, V.; Rotger, M.; He, Y.; Hollenstein, H.; Quack, M.; Schmitt, U. Year: 2002 Title: High-resolution spectroscopy of the v3 band of WF6 and ReF6 in a supersonic jet Journal: Journal of Chemical Physics Volume: 117 Issue: 7 Pages: 3196-3207 Abstract: We have recorded the Fourier-transform infrared (FTIR) spectrum of the v3 fundamental band of WF6 in a continuous supersonic jet expansion with an instrumental bandwidth of 0.0024 cm-1 (FWHM, full width at half maximum, unapodized), using a Bomem DA.002 spectrometer. Some parts of this band have also been recorded with 0.0007 cm-1 bandwidth using a diode laser spectrometer combined with a pulsed slit jet expansion. A multiple-pass arrangement has been used for the slit jet to observe low-intensity lines. In each case, we have used a WF6:He mixture with a seeding ratio 1:3 leading to a rotational temperature of ca. 50 K. This work extends the previous investigation of Takami and Kuze [J. Chem. Phys. 80, 5994 (1984)] to much higher J transitions. In both P and R branches, rotational lines have been recorded for J up to 46-48. We have used a tensorial Hamiltonian adapted to the group chain O(3) Oh and developed to the third order for the analysis of the spectra. A least-squares fit for each of the four main isotopic species: 182WF6, 183WF6, 184WF6, and 186WF6 results in band centers (in this order) 714.538 19, 714.214 06, 713.895 44, and 713.266 21 cm-1. We report furthermore first results on the high-resolution spectra of v3 of ReF6, which exhibits a fourfold degenerate electronic ground state of Gg' species in the OhS group. Supersonic jet-FTIR spectra show a moderately structured relatively broad band, whereas the diode laser spectroscopy of the seeded jet in the range 708-733 cm-1 results in line resolved spectra of high complexity. A preliminary analysis is discussed, while a complete analysis still represents an appreciable challenge. (C) 2002 American Institute of Physics.
Reference Type: Journal Article Author: Borysov, A.; Champion, J. P.; Jørgensen, U. G.; Wenger, C. Year: 2002 Title: Towards simulation of high temperature methane spectra Journal: Molecular Physics Volume: 100 Issue: 22 Pages: 3585-3594 Abstract: Methane plays a central role in gas layers of temperatures up to around 3000 K in a number of astrophysical objects ranging from giant planets to brown dwarfs, over proto-solar nebulae, to several classes of cool stars. In order to model and analyse these objects correctly, an accurate and complete list of spectral lines at high temperature is demanded. Predicting high temperature spectra implies, however, predicting hot bands and thus modelling highly excited vibrational states. This is a real challenge in the case of methane. We report the preliminary results of a theoretical study combining the global effective Hamiltonian approach and its computational implementation (STDS package: http://www.u-bourgogne.fr/LPUB/shTDS.html) with semi-quantitative statistical considerations.
Reference Type: Journal Article Author: Ulenikov, O. N.; Bekhtereva, E. S.; Kozinskaia, V. A.; Zheng, J. J.; He, S. G.; Hu, S. M.; Zhu, Q. S.; Leroy, C.; Pluchart, L. Year: 2002 Title: On the study of resonance interactions and splittings in the PH3 molecule: v1, v3, v2+v4, and 2v4 bands Journal: Journal of Molecular Spectroscopy Volume: 215 Issue: 2 Pages: 295-308 Abstract: The high-resolution (0.005 cm-1) Fourier transform infrared spectrum of PH3 is recorded and analyzed in the region of the fundamental stretching bands, v1 and v3. The v2+v4 and 2v4 bands are taken into account also. Experimental transitions are assigned to the v1, v3, v2+v4, and 2v4 bands with the maximum value of quantum number J equal to 15, 15, 13, and 15, respectively. A1-A2 splittings are observed and described up to the value of quantum number K equal to 10. The analysis of A1/A2 splittings is fulfilled with a Hamiltonian model which takes into account numerous resonance interactions among all the upper vibrational states. (C) 2002 Elsevier Science (USA).
Reference Type: Journal Article Author: Pierre, G.; Boudon, V.; EB, M. Kadmi; Burger, H.; Bermejo, D.; Martinez, R. Year: 2002 Title: Study of the fundamental bands of 70GeD4 by high-resolution Raman and infrared spectroscopy: First experimental determination of the equilibrium bond length of germane Journal: Journal of Molecular Spectroscopy Volume: 216 Issue: 2 Pages: 408-418 Abstract: The four fundamental bands of 70GeD4 have been analyzed using the STDS software developed in Dijon (http://www.ubourgogne.fr/LPUB/sTDS.html). Both infrared and Raman spectra were used to observe all fundamental bands. Infrared spectra of monoisotopic 70GeD4 were recorded in the regions 600 and 1500 cm-1 using the Bruker 120HR interferometer at Wuppertal. The resolution (1/maximum optical path difference) was between 2.3 and 3.3x10-3 cm-1 or the v3 and v4 infrared-active fundamental bands as well as for the interacting v2 band. A high-resolution stimulated Raman spectrum of the v1 hand has been recorded in Madrid. The instrumental resolution of the Raman spectrum was 3.3x10-3 cm-1. We have performed a global fit of the ground state, v2/v4 bending dyad, and v1/v3 stretching dyad. We have used 1146, 139, and 676 assigned lines for v2/v4, v1, and v3, respectively. The standard deviation is 2.2x10-3 cm-1 for the bending dyad. 1.6x10-3 cm-1 for the v3 infrared lines, and 1.7x10-3 cm-1 for the v1 Raman lines. These results enabled us to perform the first experimental determination of die equilibrium bond length of germane as re=1.5173(1) Angstrom. (C) 2002 Elsevier Science (USA).
Reference Type: Journal Article Author: Rotger, M.; Boudon, V.; Loete, M. Year: 2002 Title: Spectroscopy of XY2Z2 (C2v) molecules: A tensorial formalism adapted to the O(3) of TdC2v chain. Application to the ground state of SO2F2 Journal: Journal of Molecular Spectroscopy Volume: 216 Issue: 2 Pages: 297-307 Abstract: A tensorial formalism adapted to the case of quasi-spherical XY2Z2 asymmetric tops such as SO2F2 has been developed as an extension of the usual one for the tetrahedral molecules. We use the O(3) of TdC2v group chain. All the coupling coefficients and formulas for the computation of matrix elements are given for this chain. Such relations are then deduced in the C2v group itself. We also present a development of the Hamiltonian. dipole moment, and polarizability operators for the molecules under consideration using this formalism. These operators are involved in the calculation of the energies and intensities of rovibrational transitions and are essential for spectrum simulations. Expressions for the matrix elements are derived for these operators, A first application to the ground state of SO2F2 is presented. Programs for spectrum Simulation and fit using these methods are freely available at the URL http://www.u-bourgogne.fr/LPUB/c2vTDS.html. (C) 2002 Elsevier Science (USA).
Reference Type: Journal Article Author: Nikitin, A.; Brown, L. R.; Fejard, L.; Champion, J. P.; Tyuterev, V. G. Year: 2002 Title: Analysis of the CH3D nonad from 2000 to 3300 cm-1 Journal: Journal of Molecular Spectroscopy Volume: 216 Issue: 2 Pages: 225-251 Abstract: As part of the simultaneous analysis of line positions and intensities of the first two polyads of monodeuterated methane, the results achieved for the region 3-5 microns are reported. It involves the three highest fundamentals, (v1, v2, v4), Overlapped by overtone (2v3, 2v5, 2v6) and combination (v3 + v6, v3 +v5, v5 + v6) bands. The theoretical model was based on the global tensorial model implemented in the MIRS package. Some 10 000 line positions and 2400 line intensities have been modeled to +/-0.000 88 cm-1 and +/-3.6 % respectively, using measurements obtained at 0,0056 and 0.011 cm-1 resolution with the Fourier transform spectrometer at National Solar Observatory located at Kitt Peak. The strongest band in this polyad is v4(E) at 3016.7 cm-1 with a strength of 6.3 x 10-18 cm-1/(molecule cm-2) at 296 K: the weakest band is 2v3(E) at 2597.7 cm(-1) with a strength of 1.9 x 10-20 cm-1/(molecule cm-2) at 296 K. The total calculated absorption arising from the CH3D nonad is 8.95 x 10-18 cm-1/(molecule cm-2) at 296 K. (C) 2002 Elsevier Science (USA).
Reference Type: Journal Article Author: Raballand, W.; Rotger, M.; Boudon, V.; Loete, M. Year: 2003 Title: Spectroscopy of X2Y4 (D2h) molecules: tensorial formalism adapted to the O(3) D2h chain, Hamiltonian and transition moment operators Journal: Journal of Molecular Spectroscopy Volume: 217 Issue: 2 Pages: 239-248 Abstract: A tensorial formalism adapted to the case of the X2Y4 molecules with D2h symmetry has been developed in the same way as in the previous works on XY4 (Td) and XY6 (Oh) spherical tops and XY5Z (C4v) symmetric tops. Here, we use the O(3) D2h group chain. All the coupling coefficients and formulas for the computation of matrix elements are given for this chain and used in the case of the Hamiltonian and transition moment operators. (C) 2003 Elsevier Science (USA). All rights reserved.
Reference Type: Journal Article Author: Pine, A. S.; Gabard, T. Year: 2003 Title: Multispectrum fits for line mixing in the v3 band Q branch of methane Journal: Journal of Molecular Spectroscopy Volume: 217 Issue: 1 Pages: 105-114 Abstract: First-order line-mixing coefficients and model relaxation matrix element scaling factors have been obtained for allowed transitions in the v3 band Q branch of CH4 broadened by H2, He, N2, O2, Ar, and CH4. The broadening, shifting, Dicke-narrowing, and line-mixing parameters are determined by simultaneous least-squares fitting of spectra at pressures from 0.014 to 66.66 kPa recorded with a high-resolution difference-frequency laser. These results confirm, improve, and extend a previous analysis of the lower pressure (less than or equal to13.3 kPa) data [A.S. Pine, J. Chem. Phys. 97 (1992) 773] which yielded averaged coefficients of individually fit spectra where adjacent broadened lines are still partially resolved. (C) 2002 Elsevier Science (USA). All rights reserved.
Reference Type: Journal Article Author: Pluchart, L.; Leroy, C.; Mourbat, A. Year: 2003 Title: Study of the stretching modes of the arsine molecule Journal: Journal of Molecular Spectroscopy Volume: 218 Issue: 1 Pages: 1-11 Abstract: To study local mode XY3 molecules, we use properties of the group chain U(4) U(3) K(3) S(3) = C3v. For the Hamiltonian, we deduce diagonal terms and coupling terms between bonds. We analyze the stretching modes of the arsine molecule. An algebraic transition operator is built and applied to the same molecular system. (C) 2003 Elsevier Science (USA). All rights reserved.
Reference Type: Journal Article Author: Michelot, F.; Rey, M.; Boudon, V. Year: 2003 Title: Su(4) approach to fourfold degenerate electronic states of some hexafluoride molecules Journal: Journal of Molecular Spectroscopy Volume: 220 Issue: 1 Pages: 19-44 Abstract: We show that two appropriate realizations of the su(4) algebra allow the construction of all electronic operators needed for the study of vibronic and rovibronic interactions in a G' electronic state. In each case a full bosonic realization is made and all matrix elements are calculated. Illustrations of our formalism and comparisons with previous approaches are made in the case of v5(F2g) and v3(F1u) modes. (C) 2003 Elsevier Science (USA). All rights reserved.
Reference Type: Journal Article Author: Rey, M.; Boudon, V.; Wenger, C.; Pierre, G.; Sartakov, B. Year: 2003 Title: Orientation of O(3) and SU(2)CI representations in cubic point groups (Oh, Td) for application to molecular spectroscopy Journal: Journal of Molecular Spectroscopy Volume: 219 Issue: 2 Pages: 313-325 Abstract: We propose a detailed method for the symmetrization of the standard O(3) or SU(2)CI basis |jt,m> (t = g or u) into the Oh or Td point group. This is realized by means of an orientation matrix called G. The oriented basis obtained in this way allows matrix element calculations for rovibronic spectroscopic problems concerning octahedral or tetrahedral molecules. Particular attention has been put on careful phase choices. A numerical calculation of all the G matrix elements for both integer and half-integer j values up to 399/2 has been performed. Such high angular momentum values are necessary for the case of heavy molecules with high rotational excitation. To calculate the G coefficients with high precision at high j values we pre-calculated the necessary Wigner functions using symbolic MAPLE software and made then the numerical calculations with quadruple precision. The complete list of these coefficients can be obtained freely at the URL: http://www.u-bourgogne.fr/LPUB/group.html. As an illustration, we also present briefly an application to two typical spectroscopic calculations: the pure rotational levels of SF6 in its ground vibrational state and the v3 band of ReF6 (an open-shell molecule with an odd number of electrons and a fourfold degenerate electronic ground state). (C) 2003 Elsevier Science (USA). All rights reserved.
Reference Type: Journal Article Author: Brown, L. R.; Benner, D. C.; Champion, J. P.; Devi, V. M.; Fejard, L.; Gamache, R. R.; Gabard, T.; Hilico, J. C.; Lavorel, B.; Loete, M.; Mellau, G. C.; Nikitin, A.; Pine, A. S.; Predoi Cross, A.; Rinsland, C. P.; Robert, O.; Sams, R. L.; Smith, M. A. H.; Tashkun, S. A.; Tyuterev, V. G. Year: 2003 Title: Methane line parameters in HITRAN Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 82 Issue: 1-4 Pages: 219-238 Abstract: Two editions of the methane line parameters (line positions, intensities and broadening coefficients) available from HITRAN in 2000 and 2001 are described., In both versions, the spectral interval covered was the same (from 0.01 to 6184.5 cm-1), but the database increased from 48,033 transitions in 2000 to 211,465 lines in 2001 because weaker transitions of 12CH4 and new bands of 13CH4 and CH3D were included. The newer list became available in 2001 in the "Update" section of HITRAN. The sources of information are described, and the prospects for future improvements are discussed. (C) 2003 Elsevier Ltd. All rights reserved.
Reference Type: Journal Article Author: Nikitin, A.; Champion, J. P.; Tyuterev, V. G. Year: 2003 Title: The MIRS computer package for modeling the rovibrational spectra of polyatomic molecules Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 82 Issue: 1-4 Pages: 239-249 Date: Nov-dec Abstract: The MIRS spectroscopic software for the modeling of ro-vibrational spectra of polyatomic molecules is presented. It is designed for the global treatment of complex band systems of molecules to take full account of symmetry properties. It includes efficient algorithms based on the irreducible tensor formalism. Predictions and simultaneous data fitting (positions and intensities) are. implemented as well as advanced options related to group theory algebra. Illustrative examples on CH3D, CH4, CH3Cl and PH3 are reported and the present status of data available is given. It is written in C++ for standard PC computer operating under Windows. The full package including on-line documentation and recent data is freely available at the URL: http://www.u-bourgogne.fr/LPUB/MIRS.html. (C) 2003 Elsevier Ltd. All rights reserved.
Reference Type: Journal Article Author: Fejard, L.; Gabard, T.; Champion, J. P. Year: 2003 Title: Calculated line broadening coefficients in the v2 band of CH3D perturbed by helium Journal: Journal of Molecular Spectroscopy Volume: 219 Issue: 1 Pages: 88-97 Abstract: Line broadening coefficients have been calculated, at room temperature, for lines in the P and R branches of the v2, band of monodeuterated methane. A properly symmetrized semiclassical model with parabolic relative trajectories has been used. Two interaction potential models have been considered. The first is a Lennard-Jones type atom-atom potential, while the second one was derived from ab initio calculations. The calculated line widths were compared to the available experimental data and a satisfactory agreement was found, although the model contains no other adjustable parameters than the four atomic Lennard-Jones ones. Nonetheless, failures of calculations have also been evidenced for the highest rotational quantum numbers. (C) 2003 Elsevier Science (USA). All rights reserved.
Reference Type: Journal Article Author: Rotger, M.; Boudon, V.; Loete, M.; Margules, L.; Demaison, J.; Mader, H.; Winnewisser, G.; Muller, H. S. P. Year: 2003 Title: The ground state rotational spectrum of SO2F2 Journal: Journal of Molecular Spectroscopy Volume: 222 Issue: 2 Pages: 172-179 Abstract: The analysis of the ground state rotational spectrum Of SO2F2 [K. Sarka, J. Demaison, L. Margules, I. Merke, N. Heineking, H. Burger, H. Ruland, J. Mol. Spectrosc.200 (2000) 55] has been performed with the Watson's Hamiltonian up to sextic terms but shows some limits due to the A and S reductions. Since SO2F2 is a quasi-spherical top, it can also be regarded as derived from an hypothetical XY4 molecule. Thus we have developed a new tensorial formalism in the O(3) superset of Td superset of C2v group chain [M. Rotger, V. Boudon, M. Loete, J. Mol. Spectrosc.216 (2002) 297]. We test it on the ground state of this molecule using the same experimental data (10 GHz-1 THz region, J up to 99). Both fits are comparable even if the formalisms are slightly different. This paper intends to establish a link between the classical approach and the tensorial formalism. In particular, our tensorial parameters at a given order of the development are related to the usual ones. Programs for spectrum simulation and fit using these methods are named C2vTDS. They are freely available at the URL: http://www.u-bourgogne.fr/LPUB/c2vTDS. html. (C) 2003 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; Lacome, N. Year: 2003 Title: High-resolution FTIR spectrum and analysis of the v2+v4 combination band of 32SF6 Journal: Journal of Molecular Spectroscopy Volume: 222 Issue: 2 Pages: 291-295 Abstract: The spectroscopic knowledge of sulfur hexafluoride, which is necessary for a correct remote sensing and monitoring of this species in the Earth's atmosphere, is still very partial. In particular, the hot bands in the strongly absorbing v3 region (near 948 cm-1) have not been analyzed yet. Their study implies the analysis of many vibrational levels and thus the spectroscopy of various fundamental, harmonic, and combination bands. The present work is a new contribution to this topic, concerning the v2+v4 combination band. The FTIR spectrum of this region has been recorded at room temperature with a resolution of 0.002 cm-1. The data have been analyzed thanks to the HTDS software (http://www.u-bourgogne.fr/LPUB/shTDS.html) developed in Dijon for XY6 octahedral molecules. Seven hundred and fifty-nine lines could be assigned up to J = 112, and the standard deviation is 0.0022 cm-1. The distance between the two vibrational sublevels with respective symmetry F1u and F2u is 0.348 cm-1. (C) 2003 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Nikitin, A.; Fejard, L.; Champion, J. P.; Burger, H.; Litz, M.; Colmont, J. M.; Bakri, B. Year: 2003 Title: New measurements and global analysis of chloromethane in the region from 0 to 1800 cm-1 Journal: Journal of Molecular Spectroscopy Volume: 221 Issue: 2 Pages: 199-212 Abstract: New high resolution Fourier transform spectra of pure 12CH335Cl and 12CH337Cl isotopomers of chloromethane have been recorded in Wuppertal covering the region from 600 to 3800 cm-1. New rotational transitions within the v2 = 1, v5 = 1, and v3 = 2 states have been measured at Lille. A first global analysis of the lower four band systems of the molecule (700-1800 cm-1) is reported. The model was based on an effective Hamiltonian and dipole moment expressed in terms of irreducible tensor operators. A common set of 125 effective hamiltonian parameters (sixth order) has been adjusted to fit simultaneously some 1000 IR data for each of the isotopomers including 153 mm wave data for 12CH335Cl. The assignments involve 12 sets of transitions (6 cold bands, 3 hot bands, and 3 pure rotational systems for 12CH335Cl). The standard deviation was on average 0.00014 cm-1 and 175 kHz for 3 the IR and MMW data, respectively. The v3 = v6 = 1 State was analysed for the first time principally from observed hot band transitions. (C) 2003 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; Champion, J. P.; Gabard, T.; Pierre, G.; Loëte, M.; Wenger C. Year: 2003 Title: Spectroscopic tools for remote sensing of greenhouse gases CH4, CF4 and SF6 Journal: Environmental Chemistry Letters Volume: 1 Issue: 1 Pages: 86-91 Abstract: Highly symmetrical molecules such as CH4, CF4 or SF6 are known to be atmospheric pollutants and greenhouse gases. High-resolution spectroscopy in the infrared is particularly suitable for the monitoring of gas concentration and radiative transfers in the earth’s atmosphere. This technique requires extensive theoretical studies for the modeling of the spectra of such molecules (positions, intensities and shapes of absorption lines). Here, we have developed powerful tools for the analysis and the simulation of absorption spectra of highly symmetrical molecules. These tools have been implemented in the spherical top data system (STDS) and highly-spherical top data system (HTDS) software available at http://www.u-bourgogne.fr/LPUB/shTDS.html. They include a compilation of modeled data obtained during the last 20 years. An overview of our latest results in this domain will be presented.
Reference Type: Journal Article Author: Tabyaoui, A.; Pierre, G.; Burger, H. Year: 2004 Title: Analysis of the hot band of stannane 116SnH4 in the 600-850 cm-1 range Journal: European Physical Journal D Volume: 28 Issue: 1 Pages: 49-57 Abstract: The FTIR spectrum of monoisotopic stannane 116SnH4 has been recorded in the 600-850 cm-1 range, with the Bruker 120 HR interferometer at Giessen, Germany. The resolution was 2.1 x 10-3 cm-1. The analysis of infrared transitions in this region enabled Brunet et al. to assign many lines to the bending dyad v2/v4. However, several lines in this spectrum were found to be unassigned. In a recent work, we have analysed the infrared spectrum of stannane in the bending triad region at 1400 cm-1. The results obtained enabled us to assign directly, for the spectrum in the region 600-850 cm-1, 163 of the observed transitions to the hot band {bending triad} - {bending dyad} up to J = 9. These transitions were combined to the infrared data corresponding to the bending triad (2v2,v2 + v4,2v4), to refine a set of Hamiltonian parameters for the two bands 2v2 and (v2 + v4).
Reference Type: Journal Article Author: Ulenikov, O. N.; Bekhtereva, E. S.; Kozinskaia, V. A.; Zheng, J. J.; He, S. G.; Hu, S. M.; Zhu, Q. S.; Leroy, C.; Pluchart, L. Year: 2004 Title: High-resolution spectrum of the v1+v4(E), v3+v4(E), v3+v4(A1), and v3+v4(A2) bands of the PH3 molecule: assignments and preliminary analysis Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 83 Issue: 3-4 Pages: 599-618 Date: Feb Abstract: The high-resolution (0.005 cm-1) Fourier transform infrared spectrum of PH3 is recorded in the region between 3280 and 3580 cm-1 where the following bands are located: v1+v4(E), v3+v4(E), v3+v4(A1), forbidden on symmetry band v3+v4(A2), and very weak bands v1 + v2(A1), v2 + v3(E). Transitions are assigned to the first four ones. Vibrational analysis of known experimental data is made. (C) 2003 Elsevier Ltd. All rights reserved.
Reference Type: Journal Article Author: Michelot, F. Year: 2004 Title: Symmetry adaptation of spherical tensor quantities in cubic point groups: comments on a paper by M. Rey et al Journal: Journal of Molecular Spectroscopy Volume: 224 Issue: 2 Pages: 131-136 Abstract: We underline some inconsistencies in the work [J. Mol. Spectrosc.219 (2003) 313] concerning symmetry adaptation in cubic groups. Also we show that some rather complicated methods presented can be easily avoided. (C) 2004 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Michelot, F.; Rey, M. Year: 2004 Title: u(2) su* (2) G symmetry adaptation for powers of E irreducible representations of point groups Journal: European Physical Journal D Volume: 30 Issue: 2 Pages: 181-199 Abstract: Several problems in molecular spectroscopy involve two degrees of freedom to which a two dimensional irreducible representation of a point group is associated. We show that a unified treatment of such situations can be given within the u(2) representation theory.
Reference Type: Journal Article Author: Brown, L. R.; Nikitin, A.; Benner, D. C.; Devi, V. M.; Smith, M. A. H.; Fejard, L.; Champion, J. P.; Tyuterev, V. G.; Sams, R. L. Year: 2004 Title: Line intensities of CH3D in the triad region: 6-10 microns Journal: Journal of Molecular Structure Volume: 695 Special Iss. Pages: 181-188 Abstract: Line intensities of the three lowest fundamentals of the 12CH3D triad are modeled with an RMS of 3.2% using over 2 100 observed values retrieved by multispectrurn fitting of enriched sample spectra recorded with two Fourier transform spectrometers. The band strengths of the Triad in units of 10-18 cm-1/(molecule cm-2) at 296 K are, respectively, 2.33 for v6(E) at 1161 cm-1, 1.75 for v3 (A1) at 1307 cm-1 and 0.571 for v5 (E) at 1472 cm-1. The total calculated absorption arising from 12CH3D triad fundamentals is 4.65 x 10-18 cm-1/(molecule cm-2) at 296 K. In addition. some 740 intensities of nine hotbands are fitted to 8.1%; most of the hotband measurements belong to 2v6 - v6 and v3 + v6 - v3 near 1160 cm-1 2v3 - v3 near 1290 cm-1 and v3 + v6 - v6 near 1304 cm-1. The other observed hotbands are v5 + v6 - v6, 2v5 - v5, v5 + v6 - v5, v3 + v5 - v3, and v3 + v5 - v5. (C) 2004 Elsevier B.V. All rights reserved.
Reference Type: Journal Article Author: Ulenikov, O. N.; Bekhtereva, E. S.; Grebneva, S. V.; Burger, H.; Jerzembeck, W.; Leroy, C. Year: 2004 Title: High-resolution study of some doubly excited vibrational states of PH2D: the v1+v2, v2+v5, v2+v3, and v2+v6 bands Journal: Journal of Molecular Spectroscopy Volume: 226 Issue: 1 Pages: 7-23 Abstract: The absorption bands v1+v2, v2+v5, v2+v3, and v2+v6 of PH2D have been recorded for the first time using a high-resolution Bruker 120 HR interferometer, and rotationally analyzed. Some transitions belonging to the very weak band v2+v5 and enhanced in intensity by strong interactions with the v1+v2 band were also assigned. Sets of parameters obtained from the fit reproduce experimental line position of the bands v1+v2 and v2+v3 with about the experimental accuracy. The residuals of the ro-vibrational energies of the v2+v6 band are about 10 times larger. Reasons for the poorer reproduction of the latter data are given. (C) 2004 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Gabard, T.; Grigoriev, I. M.; Grigorovich, N. M.; Tonkov, M. V. Year: 2004 Title: Helium and argon line broadening in the v2 band of CH4 Journal: Journal of Molecular Spectroscopy Volume: 225 Issue: 2 Pages: 123-131 Abstract: The spectra of the gaseous mixtures CH4-He and CH4-Ar were obtained in the spectral region 1400-1750 cm-1 with a resolution tip to 0.003 cm-1. Helium and argon pressure broadenings for the vibration-rotation lines of the v2 band of CH4 have been estimated at room temperature for some lines in the P, Q, and R branches. These values were also calculated using the theoretical approach developed by Robert and Bonamy, extended to the case of tetrahedral molecules. The helium data have been found to be in a satisfactory agreement whereas a divergence of calculated and measured broadening coefficients has been evidenced in the case of argon. Simulations of the v2 band shapes of methane perturbed by helium have also been performed. (C) 2004 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Raballand, W.; Benoit, N.; Rotger, M.; Boudon, V. Year: 2004 Title: Diode laser spectroscopy of the v8 band of the SF5Cl molecule Journal: Spectrochimica Acta Part a Molecular and Biomolecular Spectroscopy Volume: 60 Issue: 14 Pages: 3403-3412 Abstract: Diode laser spectra of SF5Cl have been recorded in the v8 band region at a temperature of ca. 240 K, a pressure of 0.25 mbar and an instrumental bandwidth of ca. 0.001 cm-1. Four regions have been studied: a first one in the P-branch (906.849-907.687 cm-1), a second one in the Q-branch (910.407-910.944 cm-1), and two other ones in the R-branch (913.957-914.556 and 917.853-918.705 cm-1), The whole v1/v8 dyad of SF535Cl has been previously recorded in the group of Professor H. Burger in Wuppertal, thanks to a Fourier transform infrared spectrometer [J. Mol. Spectrosc. 208 (2001) 169]. These data have thus been combined with our diode laser ones in the aim of refining the analysis. We used an effective Hamiltonian developed up to the fourth order and a set of programs called C4vTDS. One thousand three hundred and forty-six transitions for v1, 495 (FTIR: 35 1; diode laser: 144) transitions for v8, and 406 ground state combination differences have been assigned and fitted. A global fit has been obtained with a rms of 0.00081 cm-1 for the v1, band, 0.0012 cm-1 for the FTIR data of the v8 band, 0.00055 cm-1 for the diode laser data of this same band, and 0.00064 cm-1 for the ground state. It appears that more data (for instance, using a supersonic jet) are still necessary to obtain a completely satisfactory analysis of the v8 region. (C) 2004 Elsevier B.V. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; Domenech, J. L.; Bermejo, D.; Willner, H. Year: 2004 Title: High-resolution Raman spectroscopy of the v1 region and Raman-Raman double resonance spectroscopy of the 2 v1-v1 band of 32SF6 and 34SF6. Determination of the equilibrium bond length of sulfur hexafluoride Journal: Journal of Molecular Spectroscopy Volume: 228 Issue: 2 Pages: 392-400 Abstract: The v1 region of 32SF6 and 34SF6 has been studied by stimulated Raman spectroscopy. For both isotopomers, a detailed analysis has been performed. Several hot bands (v1 + v6 - v6, v1 + 2v6 - 2v6, v1 + v5 - v5) have been taken into account to calculate synthetic spectra that satisfactorily reproduce the experimental data. These results, together with the previous studies of the other fundamental bands have allowed us to determine the equilibrium bond length of sulfur hexafluoride as re = 1.5560(1) Angström, in very good agreement with recent ab initio calculations. The 2v1 - v1 band has also been studied for both isotopomers by Raman-Raman double resonance spectroscopy and the resulting spectra have been analyzed. In this case, a striking difference is observed between the two isotopomers, since the 2v1 - v1 band of 34SF6 appears to have a very narrow structure that could not be rotationally resolved under the present experimental conditions. All analyses have been performed thanks to the HTDS program suite (http:// www.u-bourgogne.fr/LPUB/hTDS.html) dedicated to octahedral XY6 molecules. (C) 2004 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; Champion, J. P.; Gabard, T.; Loëte, M.; Michelot, F.; Pierre, G.; Rotger, M.; Wenger, C.; Rey, M. Year: 2004 Title: Symmetry-adapted tensorial formalism to model rovibrational and rovibronic spectra of molecules pertaining to various point groups Journal: Journal of Molecular Spectroscopy Volume: 228 Issue: 2 Pages: 620-634 Abstract: We present a short review on the tensorial formalism developed by the Dijon group to solve molecular spectroscopy problems. This approach, originally devoted to the rovibrational spectroscopy of highly symmetrical species (spherical tops) has been recently extended in several directions: quasi-spherical tops, some symmetric and asymmetric tops, and rovibronic spectroscopy of spherical tops in a degenerate electronic state. Despite its apparent complexity (heavy notations, quite complex mathematical tools), these group theoretical tensorial methods have a great advantage of flexibility: a systematic expansion of effective terms for any rovibrational/rovibronic problem up to a given order is automatically generated. Inclusion of all possible interaction terms for any polyad scheme is therefore easy. This makes such an approach suitable for many types of molecular problems, not only the most symmetric ones. (C) 2004 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Wenger, C.; Raballand, W.; Rotger, M.; Boudon, V. Year: 2005 Title: D2h top data system (D2hTDS) software for spectrum simulation of X2Y4 asymmetric molecules Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 95 Issue: 4 Pages: 521-538 Abstract: The D2hTDS (D2h Top Data System) program suite has been developed with the aim of studying any rovibrational band or polyad of X2Y4 (D2h) asymmetric top molecules. It is based on the same principles as similar programs from our group already released for various molecular symmetries (Td, Oh, C4v, C2v). We work in the O(3) D2h chain and this choice has consequences on the method used to specify the input parameters of the programs for Hamiltonian and transition moment calculations. Two examples concerning the v12 and v2 bands of the C2H4 Molecule are presented. This suite consists of a series of FORTRAN programs called by a script. The whole package is freely accessible through ftp (user anonymous) at jupiter.u-bourgogne.fr or through the World Wide Web at http://www.u-bourgogne.fr/LPUB/d2hTDS.html
Reference Type: Journal Article Author: Terki Hassaine, M.; Pierre, G.; Boudon, V.; Hamadouche, G. A.; Guelachvili, G. Year: 2005 Title: The hot bands of silane between 2120 and 2270 cm-1 Journal: Journal of Molecular Spectroscopy Volume: 230 Issue: 2 Pages: 117-124 Abstract: The infrared spectrum of the SiH4 molecule has been recorded between 2040 and 2320 cm-1 using the high-resolution Fourier interferometer of the Laboratoire de Photophysique Moleculaire (Orsay, France). The resolution was 5.4 x 10-3 cm-1. In this region, many lines were previously analyzed and assigned to the v1/v3 stretching dyad of 28SiH4, 29SiH4, and 30SiH4 molecules [J. Mol. Spectrosc. 143 (1990) 35]. However, several lines in the spectrum were not assigned. The results obtained in our previous study [J. Mol. Spectrosc. 197 (1999) 307] of the infrared spectrum of 28SiH4, in the bending-stretching tetrad region at 3100 cm-1, enabled us to assign 204 of the observed transitions to hot bands (the v1+v2/v1+v4/v2+v3/v3+v4 bending-stretching tetrad minus the v2/v4 bending dyad). These transitions were used to refine the set of the Hamiltonian parameters of the bending- stretching tetrad. The analysis is performed using the tensorial formalism developed in Dijon for tetrahedral molecules and implemented in the STDS software (http://www.u-bourgogne.fr/LPUB/shTDS.html). (c) 2004 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Wenger, C.; Rotger, M.; Boudon, V. Year: 2005 Title: C2v top data system (C2vTDS) software for infrared spectrum simulation Of XY2Z2 asymmetric molecules: some improvements to the TDS packages Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 93 Issue: 4 Pages: 429-446 Abstract: The spherical top data system (STDS) program suite developed in Dijon has been extended with the aim of studying any rovibrational band or polyad of XY2Z2 (C2v) asymmetric top molecules. We work in the O(3) TdC2v chain because these species result from the substitution of two ligands of a corresponding "parent" spherical top and thus are relatively close to tetrahedral symmetry. The choice of this group chain has consequences on the method used to specify the input parameters of the programs for Hamiltonian and transition moment model calculations. One example concerning the ground state of the SO2F2 quasispherical molecule is presented. As before, this suite consists in a series of FORTRAN programs called by a script. The whole package is freely accessible through ftp (user anonymous) at jupiter.u-bourgogne.fr/dist or through the World Wide Web at http://www.u-bourgogne.fr/LPUB/c2vTDS.html. Further general improvements have been brought about for all the TDS packages (STDS, HTDS, C4vTDS) developed in our group and are briefly discussed in the present paper. (C) 2004 Elsevier Ltd. All rights reserved.
Reference Type: Journal Article Author: Nikitin, A.; Champion, J. P. Year: 2005 Title: New ground state constants of 12CH335Cl and 12CH337Cl from global polyad analysis Journal: Journal of Molecular Spectroscopy Volume: 230 Issue: 2 Pages: 168-173 Abstract: A global analysis of the infrared spectrum of chloromethane involving the ground state and the 13 vibrational states lying up to 2600 cm-1 was recently achieved using high resolution Fourier transform spectra of pure isotopomers. More than 20 000 transitions (cold and hot bands) for each isotopomer 12CH335Cl and 12CH337Cl have been assigned and fitted with a standard deviation of about 3 x 10-4 cm-1 close to the experimental precison. As part of this global effort, improved ground state constants up to sextic centrifugal distortion terms have been determined for each isotopomer taking advantage of the numerous allowed and perturtation-allowed transitions simultaneously fitted using our global model. The axial constants could be determined from Delta K not equal 0 combinations arising from rovibrational local resonances within polyads 3 and 5. (c) 2004 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Nikitin, A.; Champion, J. P.; Burger, H. Year: 2005 Title: Global analysis of 12CH335Cl and 12CH337Cl: simultaneous fit of the lower five polyads (0-2600 cm-1) Journal: Journal of Molecular Spectroscopy Volume: 230 Abstract: The global analysis of the infrared spectrum of chloromethane involving the ground state and the 13 vibrational states lying up to 2600 cm-1 is reported. This work incorporates and extends to the fifth polyad, the preliminary study of the lower four polyads published by [J. Mol. Spectrosc. 221 (2003) 199]. More than 20000 transitions (including numerous hot bands) for each isotopomer 12CH335Cl and 12CH337Cl have been assigned and fitted with a standard deviation of about 3 x 10-4 cm-1 close to the experimental precision. A common set of 288 (resp. 303) effective parameters was determined for each isotopomer. Our global model allowed us to reproduce simultaneously and accurately the resonances already encountered in polyad 3 and the new ones involved in polyad 5. (c) 2004 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Michelot, F.; Rey, M. Year: 2005 Title: Effective Hamiltonian approach to doubly degenerate electronic states - I - Theory and applications to E (b1+b2) and related Jahn-Teller systems Journal: European Physical Journal D Volume: 33 Issue: 3 Pages: 357-386 Abstract: Several problems in vibronic spectroscopy are solved within the effective Hamiltonian formalism combined with Lie algebraic methods. We consider mainly vibronic interactions in orbital doublets for molecules with a principal symmetry axis of order n=4k (or n even for Dnd symmetry groups). Effective Hamiltonian models for E (b1+b2), E (bi+aj) and E (bi+e) Jahn- Teller dynamical systems are discussed as well as some correlations with previous studies established.
Reference Type: Journal Article Author: Pluchart, L.; Leroy, C.; Sanzharov, N.; Michelot, F.; Bekhtereva, E.; Ulenikov, O. Year: 2005 Title: Vibrational modes of the stibine molecule Journal: Journal of Molecular Spectroscopy Volume: 232 Issue: 2 Pages: 119-136 Abstract: In this paper, we use the algebraic approach to describe the vibrational modes of stibine molecule (of C3v molecular symmetry group) up to 21 quanta. As the stibine molecule exhibits stretch-bend resonances, we build an algebraic pyramidal coupling operator between stretching modes and bending modes adapted to this molecule. The standard deviation associated to the fit of the vibrational levels is 1.75 cm-1. (c) 2005 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; El Hilali A.; Loëte, M. Year: 2005 Title: Development of the Hamiltonian and transition moment operators of symmetric top molecules using the O(3) C∞vC3v group chain Journal: Journal of Molecular Spectroscopy Volume: 234 Issue: 1 Pages: 176-81 Abstract: We present a development of the Hamiltonian, dipole moment, and polarizability operators for XY3Z molecules. These rovibrational operators are written with the aid of a tensorial formalism derived from the one already used in Dijon and adapted to the XY3Z symmetric tops in a recent paper [A. El Hilali, V. Boudon, M. Loete, J. Mol. Spectrosc. 234 (2005) 166-174]. We use the O(3) C∞vC3v group chain. Expressions for the matrix elements are derived for these operators. [All rights reserved Elsevier]
Reference Type: Journal Article Author: Boudon, V.; El Hilali A.; Loëte, M. Year: 2005 Title: Spectroscopy of XY3Z (C3v) molecules: A tensorial formalism adapted to the O(3) C∞vC3v group chain Journal: Journal of Molecular Spectroscopy Volume: 234 Issue: 1 Pages: 113-21 Abstract: A tensorial formalism adapted to the case of XY3Z symmetric tops has been developed. We use the O(3) C∞vC3v group chain. All the coupling coefficients and formulas for the computation of the matrix elements are given for this chain. Such relations are also deduced in C3v group itself. [All rights reserved Elsevier]
Reference Type: Journal Article Author: Rouzee, A.; Boudon, V.; Lavorel, B.; Faucher, O.; Raballand,W. Year: 2005 Title: Rotational Raman spectroscopy of ethylene using a femtosecond time-resolved pump-probe technique Journal: Journal of Chemical Physics Volume: 123 Issue: 15 Pages: 154309-1-6 Abstract: Femtosecond Raman-induced polarization spectroscopy (RIPS) was conducted at low pressure (250 mb at 295 K and 400 mb at 373 K) in ethylene. The temporal signal, resulting from the beating between pure rotational coherences, was measured with a heterodyne detection. The temporal traces were converted to the frequency domain using a Fourier transformation and then analyzed thanks to the D2hTDS software (http://www.u-bourgogne.fr/LPUB/shTDS.html) dedicated to X2Y4 molecules with D2h symmetry. The effective Hamiltonian was expanded up to order 2, allowing the determination of five parameters with an rms of 0.017 cm-1. Special care was taken in the precise modeling of intensities, taking into account all instrumental effects. Relative intensities were fitted (with an rms of 7.2 %) and two polarizability operators were determined
Reference Type: Journal Article Author: Ulenikov, O.; Leroy, C.; Bekhtereva, E.; Onopenko, G.; Chudinova, T. Year: 2005 Title: High resolution study of the six lowest doubly excited vibrational states of PH2D Journal: Journal of Molecular Spectroscopy Volume: 234 Issue: 2 Pages: 228-37 Abstract: The five lowest doubly excited deformational vibrational bands v4+v6, 2v6, v3+v4, v3+v6, and 2v3 of PH2D have been recorded for the first time using a Bruker 120 HR interferometer with a resolution 0.0033 cm-1 and analysed. Some transitions belonging to a very weak band 2v4 have been also assigned. From the fit 24 and 86, respectively, diagonal and resonance interaction parameters were obtained which reproduce 1089 upper energy levels obtained from more than 4600 assigned transitions with the rms deviation of 0.00059 cm-1. [All rights reserved Elsevier]
Reference Type: Journal Article Author: Tran, H.; Flaud, P.-M.; Gabard, T.; Hase, F.; von-Clarmann, T.; Camy-Peyret, C.; Payan, S.; Hartmann, J.-M. Year: 2006 Title: Model, software and database for line-mixing effects in the v3 and v4 bands of CH4 and tests using laboratory and planetary measurements-I: N2 (and air) broadenings and the Earth atmosphere Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 101 Issue: 2 Pages: 284-305 Abstract: Absorption spectra of the infrared v3 and v4 bands of CH4 perturbed by N2 over large ranges of pressure and temperature have been measured in the laboratory. A theoretical approach accounting for line mixing is proposed to (successfully) model these experiments. It is similar to that of Pieroni et al. [J Chem Phys 1999;110:7717-32] and is based on state-to-state rotational cross-sections calculated with a semi-classical approach and a few empirical parameters. The latter, which enable switching from the state space to the line space, are deduced from a fit of a single room temperature spectrum of the v3 band at 50 atm. The comparisons between numerous measured and calculated spectra under a vast variety of conditions (v3 and v4 0-500 atm, 170-300K) then demonstrate the quality and consistency of the proposed model. This success is a first validation of a database and associated software built in order to model the shape of CH4 absorption in air, that are available and suitable for the updating of atmospheric radiative transfer codes. The accuracy of these tools is then further demonstrated using transmission measurements of the Earth atmosphere in the v3 region (3 microns) recorded in solar absorption with ground and balloon based Fourier transform instruments. Similar tests in the v4 region using satellite based emission spectra and ground-based transmission measurements confirm the model quality although they show very small line-mixing effects and their masking by strong contributions of other species. [All rights reserved Elsevier]
Reference Type: Journal Article Author: Tran, H.; Flaud, P.-M.; Fouchet, T.; Gabard, T.; Hartmann, J.-M. Year: 2006 Title: Model, software and database for line-mixing effects in the v3 and v4 bands of CH4 and tests using laboratory and planetary measurements-II: H2 (and He) broadening and the atmospheres of Jupiter and Saturn Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 101 Issue: 2 Pages: 306-324 Abstract: The absorption shapes of the v2, v3 and v4 infrared bands of CH4 perturbed by H2 in large ranges of pressure and temperature have been measured in the laboratory. In order to model these spectra, the theoretical approach accounting for line-mixing effects proposed for CH4-N2 and CH4-air and successfully tested in the companion paper (I), is used. As before, state-to-state rotational rates are used together with some empirical parameters that are deduced from a fit of a single room temperature spectrum of the v3 band at about 50 atm. The comparisons between measured and calculated spectra in the v3 and v4 regions under a vast variety of conditions (9-300atm, 80-300K) then demonstrate the quality and consistency of the proposed model. In the case of the v2 band, which is of E symmetry, specific parameters, different from those adapted to the v3 and v4 transitions of F2 symmetry, are used for proper modeling of the spectral shape. Furthermore, as shown previously, a broad absorption feature grows underneath the v2 band with increasing H2 density. The latter, for which an empirical model is proposed, is attributed to a collision-induced absorption (CIA) process in methane. From the developed models, a database and associated software are built for the updating of planetary atmospheres radiative transfer codes. The quality of these tools is then further demonstrated using emission measurements of the Jovian and Saturnian atmospheres in the v4 region (7-10 microns) recorded by the Short Wave Spectrometer of the Infrared Space Observatory and the Composite Infrared Spectrometer on-board Cassini. Comparisons between measured radiances and predictions confirm the failure of the purely Lorentzian approach and the quality of the proposed line-mixing model. Furthermore, it is shown that the methane CIA contribution has a significant influence on the planetary emission beyond 1400 cm-1. [All rights reserved Elsevier]
Reference Type: Journal Article Author: Rouzée, A.; Guérin, S.; Boudon, V.; Lavorel, B.; Faucher, O. Year: 2006 Title: Field-free one-dimensional alignment of ethylene molecule - art. no. 33418 Journal: Physical Review A Atomic, Molecular, and Optical Physics Volume: 73 Issue: 3 Pages: 33418-1 - 33418-9 Abstract: We report an experimental study of nonadiabatic laser-induced molecular alignment of ethylene (C2H4) using a linearly polarized short laser pulse of moderate intensity. The information about the confinement of the C=C bond axis along the direction of the applied electric field is obtained by measuring the depolarization of a second short pulse of weak intensity interacting with the molecules after they have been exposed to the first pulse. The experimental data are compared with the numerical simulation of the Schrodinger equation written for the nonresonant interaction of an asymmetric top rigid rotor with a linearly polarized electric field. The field-free alignment is described by analyzing the time evolution of the angular distribution of the molecular axes together with the expectation value of the relevant squared direction cosine matrix elements
Reference Type: Journal Article Author: Boudon, V.; Rey, M.; Loëte, M. Year: 2006 Title: The vibrational levels of methane obtained from analyses of high-resolution spectra Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 98 Issue: 3 Pages: 394-404 Abstract: Methane and its tetrahedral isotopologues are spherical-top molecules whose high-resolution rovibrational spectra can only be analyzed in detail, thanks to sophisticated symmetry-adapted tensorial models. However, the effective Hamiltonian parameters of such models do not give direct access to the positions of the vibrational sublevels. In this paper, we present a calculation of the vibrational level positions for 12CH4, 13CH4, 12CD4 and 13CD4 performed using the effective Hamiltonian parameters obtained through recent analyses. We also include the results of a re-analysis of the octad system of 12CH4 performed with a higher order of the development which slightly improves the previous work on this polyad. [All rights reserved Elsevier]
Reference Type: Journal Article Author: Coustenis, A.; Negrão, A.; Salama, A.; Schulz, B.; Lellouch, E.; Rannou, P.; Drossart, P.; Encrenaz, T.; Schmitt, B.; Boudon, V.; Nikitin, A. Year: 2006 Title: Titan's 3-micron spectral region from ISO high-resolution spectroscopy Journal: Icarus Volume: 180 Issue: 1 Pages: 176-185 Abstract: The near-infrared spectrum of Titan, Saturn's largest moon and one of the Cassini/Huygens' space mission primary targets, covers the 0.8 to 5 micron region in which it shows several weak CH4 absorption regions, and in particular one centered near 2.75 micron. Due to the interference of telluric absorption, only part of this window region (2.9-3.1 microns) has previously been observed from the ground [Noll, K.S., Geballe, T.R., Knacke, R., Pendleton, F., Yvonne, J., 1996. Icarus 124, 625-631; Griffith, C.A., Owen, T., Miller, G.A., Geballe, T., 1998. Nature 395, 575-578; Griffith, C.A., Owen, T., Geballe, T.R., Rayner, J., Rannou, P., 2003. Science 300, 628-630; Geballe, T.R., Kim, S.J., Noll, K.S., Griffith, C.A., 2003. Astrophys. J. 583, L39-L42]. We report here on the first spectroscopic observations of Titan covering the whole 2.4-4.9 microns region by two instruments on board the Infrared Space Observatory (ISO) in 1997. These observations show the 2.75 microns window in its complete extent for the first time. In this study we have also used a high-resolution Titan spectrum in the 2.9-3.6 microns region taken with the Keck [Geballe, T.R., Kim, S.J., Noll, K.S., Griffith, C.A., 2003. Astrophys. J. 583, L39-L42; Kim, S.J., Geballe, T.R., Noll, K.S., Courtin, R., 2005. Icarus 173, 522-532] to infer information on the atmospheric parameters (haze extinction, single scattering albedo, methane abundance, etc.) by fitting the methane bands with a detailed microphysical model of Titan's atmosphere (updated from Rannou, P., McKay, C.P., Lorenz, R.D., 2003. Planet. Space Sci. 51, 963-976). We have included in this study an updated version of a database for the CH4 absorption coefficients [STDS, Wenger, Ch., Champion, J.-P., 1998. J. Quant. Spectrosc. Radiat. Transfer 59, 471-480. See also http://www.u-bourgogne.fr/LPUB/TSM/sTDS.html for latest updates; Boudon, V., Champion, J.-P., Gabard, T., Loete, M., Michelot, F., Pierre, G., Rotger, M., Wenger, Ch., Rey, M., 2004. J. Mol. Spectrosc. 228, 620-634]. For the atmosphere we find that (a) the haze extinction profile that best matches the data is one with higher (by 40%) extinction in the atmosphere with respect to Rannou et al. (2003) down to about 30 km where a complete cut-off occurs; (b) the methane mixing ratio at Titan's surface cannot exceed 3 % on a disk-average basis, yielding a maximum CH4 column abundance of 2.27 km-am in Titan's atmosphere. From the derived surface albedo spectrum in the 2.7-3.08 microns region, we bring some constraints on Titan's surface composition. The albedo in the center of the methane window varies from 0.01 to 0.08. These values, compared to others reported in the other methane windows, show a strong compatibility with the water ice spectrum in the near-infrared. Without confirming its existence from this work alone, our data then appear to be compatible with water ice. A variety of other ices, such as CO2, NH3, tholin material or hydrocarbon liquid cannot be excluded from our data, but an additional unidentified component with a signature around 2.74 microns is required to satisfy the data. [All rights reserved Elsevier]
Reference Type: Journal Article Author: Michelot, F. Year: 2006 Title: Algebraic treatment of some systems with spin-like interactions with applications in quantum optics and vibronic spectroscopy Journal: Journal of Physics A Mathematical and General Volume: 39 Issue: 20 Pages: 5933-5656
Abstract: A unified scheme based on algebraic techniques is proposed to solve the eigenvalue equation for a class of systems involving spin-like interactions. From general assumptions Hamiltonian models are built from selected elements in the enveloping algebra of the harmonic oscillator, su(2) and su(1, 1) algebras. Our method is next illustrated through examples taken in the areas of quantum optics and dynamical Jahn-Teller systems in orbital doublets
Reference Type: Journal Article Author: Griffith, C. A.; Penteado, P.; Rannou, P.; Brown, R.; Boudon, V.; Baines, K. H.; Clark, R.; Drossart, P.; Buratti, B.; Nicholson, P.; McKay, C. P.; Coustenis, A.; Negrão, A.; Jaumann, R. Year: 2006 Title: Evidence for a polar ethane cloud on Titan Journal: Science Volume: 313 Issue: 5793 Pages: 1620-1622 Abstract: Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal the presence of a vast tropospheric cloud on Titan at latitudes 51 degrees to 68 degrees north and all longitudes observed (10 degrees to 190 degrees west). The derived characteristics indicate that this cloud is composed of ethane and forms as a result of stratospheric subsidence and the particularly cool conditions near the moon's north pole. Preferential condensation of ethane, perhaps as ice, at Titan's poles during the winters may partially explain the lack of liquid ethane oceans on Titan's surface at middle and lower latitudes.
Reference Type: Journal Article Author: El Hilali, A.; Boudon, V.; Loete, M. Year: 2006 Title: Spectroscopy of XY3Z (C3v) radicals with an odd number of electrons: A tensorial formalism adapted to the SU(2)CIC∞vSC3vS group chain Journal: Journal of Molecular Spectroscopy Volume: 239 Issue: 1 Pages: 41-50 Abstract: A tensorial formalism adapted to the case of XY3Z symmetric tops with half integer angular momenta is proposed as an extension of the formalism for the group chain O(3)C∞vC3v developed in a recent paper [A. El Hilali, V. Boudon, M. Loete, J. Mol. Spectrosc. 234 (2005) 113-121]. We use the chain SU(2)CIC∞vSC3vS, where GS (G being C∞v or C3v) is the G point group with its spinorial representations. Coupling coefficients and formulas for the computation of matrix elements of the tensor operators are derived for this chain. A deduction of coupling coefficients (Clebsch-Gordan, 6C, 9C, ...) and similar formulas is proposed for the group C3vS itself. (c) 2006 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; Doménech, J. L.; Ramos, A.; Bermejo, D.; Willner, H. Year: 2006 Title: High-resolution stimulated Raman spectroscopy and analysis of the v2, v5 and 2v6 bands of 34SF6 Journal: Molecular Physics Volume: 104 Issue: 16-17 Pages: 2653-2661 Abstract: The v2, v5 and 2v6 regions of 34SF6 have been studied by stimulated Raman spectroscopy. We used an isotopically pure sample of 34SF6. A detailed analysis of the v2 and v5 fundamentals has been performed with the HTDS program suite (http://www.u-bourgogne.fr/LPUB/ hTDS.html) dedicated to octahedral XY6 molecules. We also present a preliminary analysis of the 2v6 band for both 32SF6 and 34SF6. Finally, we give the 32S - 34S isotopic shifts for all the SF6 fundamentals.
Reference Type: Journal Article Author: Crogman, H. T.; Boudon, V.; Harter, W. G.; Mitchell, J. Year: 2006 Title: Deformation of sulfur hexafluoride and floppiness of trifluoromethyl sulfur pentafluoride Journal: Molecular Physics Volume: 104 Issue: 16-17 Pages: 2781-2790 Abstract: With recent advances in space exploration and atmospheric chemistry there is an increased need for more spectroscopic tools to allow the of study complex species. One such tool is the theory of frame transformation of coupled rotor systems. In this article, the theory of frame transformation along with the concept of rotational energy surface is used to study the symmetry that occurs in trifluoromethyl sulfur pentafluoride due to the internal rotation of the CF3 radical and, more generally, to the extent of floppiness of SF5CF3. Other lower symmetries when a CF4 molecule is stuck on the various symmetry axes of an SF6 molecule are also discussed.
Reference Type: Journal Article Author: Raballand, W.; Rotger, M.; Boudon, V.; Loëte, M.; Breidung, J.; Thiel, W. Year: 2006 Title: Stark effect in X2Y4 molecules: Application to ethylene Journal: Journal of Molecular Structure Volume: 780-81 Special Iss. SI Pages: 70-79 Abstract: We present a development of the dipole moment and polarizability operators Of X2Y4 molecules, using a tensorial formalism analogous to the one developed for tetrahedral and octahedral molecules [V. Boudon, J.-P. Champion, T. Gabard, M. Loete, F. Michelot, G. Pierre, M. Rotger, Ch. Wenger, M. Rey, J. Mol. Spectrosc. 228 (2004) 620-634]. These operators are involved in the calculation of the intensities of rovibrational transitions as well as in the calculation of the Stark effect. Expressions for the matrix elements are derived. A model for the study of the Stark effect in isolated bands of such molecules is proposed and has been used to predict the Stark spectra of the v12 band of ethylene. Values of the polarizability coefficients have been calculated using ab initio methods. (c) 2005 Elsevier B.V. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; Rotger, M.; Zvereva-Loëte, N.; Loëte, M. Year: 2006 Title: The SO2F2 quasi-spherical top: Correspondence between tensorial and Watson's formalisms Journal: Journal of Molecular Structure Volume: 780-81 Special Iss. SI Pages: 124-133 Abstract: The SO2F2 quasi-spherical top molecule with C2v symmetry is considered as a distorted spherical top deriving from the SO42- tetrahedral ion. We present here a detailed correspondence between the tensorial formalism using the T-d superset of C-2v reorientation and the usual Hamiltonian of Watson. We have also performed ab initio calculations in order to determine the centrifugal distorsion constants in the vibrational ground state. (c) 2005 Elsevier B.V. All rights reserved.
Reference Type: Journal Article Author: Rotger, M.; Boudon, V.; Loëte, M.; Zvereva-Loëte, N.; Margules, L.; Demaison, J.; Merke, I.; Hegelund, F.; Burger, H. Year: 2006 Title: The bending triad of the quasi-spherical top molecule SO2F2 in the 550 cm-1 region Journal: Journal of Molecular Spectroscopy Volume: 238 Issue: 2 Pages: 145-157 Abstract: The analysis of the v3/v7/v9 bending triad of SO2F2 has been recently performed with the Watson's Hamiltonian up to octic terms employing 79 rovibrational parameters but including only the first order Coriolis interaction terms, fixed to ab initio values [H. Burger, J. Demaison, F. Hegelund, L. Margules, I. Merke, J. Mol. Struct. 612 (2002) 133-141]. Since SO2F2 is a quasi-spherical top, it can also be considered as derived from the SO42- sulfate ion. We have thus developed a new tensorial formalism in the O(3)TdC2v group chain [M. Rotger, V. Boudon, M. Loete, J. Mol. Spectrosc. 216 (2002) 297-307]. This approach allows a systematic development of rovibrational interactions and makes global analyses easier to perform even for complex polyad systems. We present here an application of this model to the analysis of the bending triad, with the same set of microwave assignments and almost the same set of infrared assignments as in the previous study of Burger et al. It appears that we need to expand our Hamiltonian to a lower degree than the "classical" one (six instead of eight) when including also the second order Coriolis interactions. Our fit does not include more parameters. Furthermore, all of them are determined and the standard deviation of the rotational transitions is twice smaller. The analysis has been performed thanks to the C-2 upsilon TDS program suite, which is freely available at the URL: http://www.u-bourgogne.fr/LPUB/c2vTDS.html. (c) 2006 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Michelot, F. Year: 2006 Title: The algebra eigenstates method for some systems with spin-like interactions Journal: Physics Letters A Volume: 354 Issue: 3 Pages: 200-209 Abstract: An extension of the algebra eigenstates formalism is proposed to solve the eigenvalue equation for a class of problems involving "spin interactions". The method is detailed for the harmonic oscillator, su(2) and su(1,1) algebras. Special emphasis is given to the resolution of problems in vibronic spectroscopy involving doubly degenerate electronic states. (c) 2006 Elsevier B.V. All rights reserved.
Reference Type: Journal Article Author: Negrao, A.; Coustenis, A.; Lellouch, E.; Maillard, J. P.; Rannou, P.; Schmitt, B.; McKay, C. P.; Boudon, V. Year: 2006 Title: Titan's surface albedo variations over a Titan season from near-infrared CFHT/FTS spectra Journal: Planetary and Space Science Volume: 54 Issue: 12 Pages: 1225-1246 Abstract: We have observed Titan in a series of campaigns from 1991 to 1996 with the Fourier Transform Spectrometer on the CFH telescope. The data acquired provide a lightcurve from the geometric albedos in the 0.9-2.5 microns spectral region. The 1991-1993 data were previously analyzed in Coustenis et al. [1995. Titan's surface: composition and variability from its near-infrared albedo. Icarus 118, 87-104] with a spherical particle code by McKay et al. [1989. The thermal structure of Titan's atmosphere. Icarus 80, 23-53]. We present here three new datasets from the 1994, 1995 and 1996 observations, with additional information from the 0.94-micron methane window on Titan. All the data (1991-1996) are re-analyzed in this work using an updated radiative transfer code based on Rannou et al. [2003. A model of Titan's haze of fractal aerosols constrained by multiple observations. Planet. Space Sci. 51, 963-976] with fractal particles. A comparative study of methane absorption coefficients currently available from different sources is also performed demonstrating the great sensitivity of surface inferences to this model parameter. Based on our results, we recommend the methane absorption coefficients produced by Boudon et al. [2006. The vibrational levels of methane obtained from analyses of high-resolution spectra. J. Quant. Spectrosc. 98, 394-404.] and Irwin-et al. [2006. Improved near-infrared methane band models and k-distribution parameters from 2000 to 9500 cm-1 and implications for interpretation of outer planet spectra. Icarus 181, 309-319.] for future studies of Titan. The geometric albedos have been reproduced with our model. We have tested different types of haze profiles and inferred the impact of this parameter on the retrieval of surface albedos. The latter are finally proposed in the atmospheric methane windows centered at 0.94, 1.075, 1.28, 1.6 and 2 microns for each of the methane coefficient sets. The surface albedos proposed here are not just points at the center of the windows but curves covering a large portion of these regions. This is useful for studies of the composition of the Titan surface. Indeed, we find our data to be compatible with mixtures of water ice and tholin but have strong indication for the presence of an additional, as yet unidentified, component (or components) for which we offer a spectral description. We also discuss the implications of the surface albedo retrievals (as a disk average) for the surface of Titan, recently investigated by the Cassini-Huygens mission. (c) 2006 Elsevier Ltd. All rights reserved.
Reference Type: Journal Article Author: Nikitin, A. V.; Champion, J. P.; Brown, L. R. Year: 2006 Title: Preliminary analysis of CH3D from 3250 to 3700 cm-1 Journal: Journal of Molecular Spectroscopy Volume: 240 Issue: 1 Pages: 14-25 Abstract: The infrared spectrum of CH3D from 3250 to 3700 cm-1 was studied for the first time to assign transitions involving the v2+v3, v2+v5, v2+v6, v3+2v6 and 3v6 vibrational states. Line positions and intensities were measured at 0.011 cm-1 resolution using Fourier transform spectra recorded at Kitt Peak with isotopically enriched samples. Some 2852 line positions (involving over 900 upper state levels) and 874 line intensities were reproduced with RMS values of 0.0009 cm-1 and 4.6%, respectively. The strongest bands were found to be v2+v3 at 3499.7 cm-1 and v2+v6 at 3342.5 cm-1 with integrated strengths, respectively, of 8.17 x 10-20 and 2.44 x 10-20 (cm-1/ molecule.cm-2) at 296 K (for 100% CH3D). The effective Hamiltonian was expressed in terms of irreducible tensor operators and adapted to symmetric top molecules. Its present configuration in the MIRS package permitted simultaneous consideration of the four lowest polyads of CH3D: the Ground State (G.S.), the Triad from 6.3 to 9.5 microns, the Nonad from 3.1 to 4.8 microns and now the Enneadecad (19 bands) from 2.2 to 3.1 microns. The CH3D line parameters for this interval were calculated to create a new database for the 3 microns region. (c) 2006 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Ulenikov, O. N.; Bekhtereva, E. S.; Bulavenkova, A. S.; Leroy, C.; Jerzembeck, W.; Burger, H. Year: 2006 Title: High resolution study of AsHD2: Ground state and the three bending fundamental bands v3, v4, and v6 Journal: Journal of Molecular Spectroscopy Volume: 240 Issue: 1 Pages: 102-111 Abstract: For the first time the infrared spectrum of the AsHD2 molecule has been measured in the region of the bending fundamental bands v3, v4, and v6 on a Fourier transform spectrometer with a resolution of 0.0024 cm-1 and analyzed. More than 5500 transitions with Jmax = 26 have been assigned and used both to obtain "ground state combination differences" and for the determination of upper state ro-vibrational energies of the triad (001000), (000100), and (000001). Rotational parameters including centrifugal distortion coefficients up to octic terms of the ground vibrational state were calculated by fitting more than 500 "ground state combination differences" with Jmax and Ka(max) = 21. The obtained set of 24 parameters provides a rms-deviation of 0.00011 cm-1. The upper energies were fitted with 52 parameters of an effective Hamiltonian which takes into account strong resonance interactions between all vibrational states of the triad (001000), (000100), and (000001). The rms-deviation for the energy levels considered in the fit is 0.00014 cm-1. (c) 2006 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Boudon, V.; Radhouani, D.; Loete, M.; Martinez, R. Z.; Bermejo, D. Year: 2007 Title: High-resolution stimulated Raman spectroscopy and analysis of the v1 stretching band of GeD4 Journal: Journal of Raman Spectroscopy Volume: 38 Issue: 5 Pages: 559-562 Abstract: The high-resolution stimulated Raman spectrum of the v1, band of GeD4 with natural isotopic abundance germanium has been recorded. It has been analyzed as part of the v1/v3 stretching dyad. The v1 and v3 band centers have been deduced for all the isotopologues. Copyright (C) 2006 John Wiley and Sons, Ltd.
Reference Type: Journal Article Author: Crogman, H.; Boudon, V.; Sadovskii, D. A. Year: 2007 Title: Local modes of silane within the framework of stretching vibrational polyads Journal: European Physical Journal D Volume: 42 Issue: 1 Pages: 61-72 Abstract: We define stretching relative equilibria (RE) of silane and other similar tetrahedral molecules in terms of the dynamical polyad symmetry which assumes the resonance condition 1:1 between the two stretching vibrational modes v1 and v3 of the molecule. Exploiting symmetry and topology arguments and reducing the dimension of the classical mechanical system, we find these RE. One of them, with local symmetry C3v. and minimal energy within a polyad, corresponds to the local modes. We give the upper energy limit of the local mode localization within a polyad.
Reference Type: Journal Article Author: Negrao, A.; Hirtzig, M.; Coustenis, A.; Gendron, E.; Drossart, P.; Rannou, P.; Combes, M.; Boudon, V. Year: 2007 Title: The 2-microns spectroscopy of Huygens probe landing site on Titan with Very Large Telescope/Nasmyth Adaptive Optics System Near-Infrared Imager and Spectrograph - art. no. E02S92 Journal: Journal of Geophysical Research Planets Volume: 112 Issue: E2 Pages: E02S92-1-14 Abstract: Several ground-based telescopes followed the event of the Huygens probe descent through Titan's atmosphere (14 January 2005). We used the Nasmyth Adaptive Optics System Near-Infrared Imager and Spectrograph (NACO) adaptive optics system at the UT-4 of the Very Large Telescope in Chile to perform both spectroscopic and imaging measurements of Titan. We present here a selected sample of the spectra we acquired on 16 January 2005 in the K band between 2.03 and 2.40 microns. Our spectra include the Huygens landing site and surrounding dark and bright areas. We apply a radiative transfer code using new methane absorption coefficients calculated in the 2-microns region. The analysis of the data yields information on the atmosphere and surface properties of these areas. The latter seem to indicate a strong decrease of Titan's surface albedo between 2.03 and 2.12 microns in all areas. This is compatible with the presence of ices such as CH4 and H2O at the surface. Sensitivity tests on the influence of the haze profile and the methane absorption on these results were performed.
Reference Type: Journal Article Author: Grisch, F.; Bertseva, E.; Habiballah, M.; Jourdanneau, E.; Chaussard, F.; Saint Loup, R.; Gabard, T.; Berger, H. Year: 2007 Title: CARS spectroscopy of CH4 for implication of temperature measurements in supercritical LOX/CH4 combustion Journal: Aerospace Science and Technology Volume: 11 Issue: 1 Pages: 48-54 Abstract: Experimental and theoretical investigations of coherent anti-Stokes Raman spectroscopy of CH4 have been carried out. Experimental spectra were measured in a heated high-pressure test cell and compared with numerical simulations. Good agreement was obtained for the temperature and the pressure dependence of CARS spectra in the ranges 300-1100 K and 0.1-5.0 MPa. The observed dependencies provide useful guidance for CARS thermometry, allowing quantitative measurements of temperature in high-pressure combustors. Application of multiplex CH4 CARS thermometry for single-shot measurements in a LOX/CH4 combustion at high pressure was demonstrated at supercritical conditions (5.6 MPa). (c) 2006 Elsevier Masson SAS. All rights reserved.
Reference Type: Journal Article Author: Jourdanneau, E.; Gabard, T.; Chaussard, F.; Saint-Loup, R.; Berger, H.; Bertseva, E.; Grisch, F. Year: 2007 Title: CARS methane spectra: Experiments and simulations for temperature diagnostic purposes Journal: Journal of Molecular Spectroscopy Volume: 246 Issue: 2 Pages: 167-179 Abstract: CARS laboratory experiments were done in the 2905-2925 cm-1 range, in the vicinity of the v1 band of the methane molecule, for pressures ranging from I to 50 bar, and temperatures up to 1100 K. These experiments were carried out in order to retrieve the pressure evolution of the CH4 spectrum, as well as to confirm its temperature dependance. After a brief recall on the theory used to compute pressure broadening coefficients and relaxation rates, we consider the v3 and v4 infrared bands of methane for benchmark calculations purposes. Next, we present recent experimental CARS spectra and calculated ones. Lastly, we discuss flame experiments as well as comparisons of temperature retrieval using N2 and CH4 as probe molecules. (c) 2007 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Michelot, F.; Rey, M. Year: 2007 Title: Effective Hamiltonian approach to doubly degenerate electronic states - II-Applications to Er x er'and G' x e dynamical Jahn-Teller systems Journal: European Physical Journal D Volume: 44 Issue: 3 Pages: 467-495 Abstract: Effective vibronic Hamiltonian models are built for E x e Jahn-Teller systems and analytical solutions are obtained through Lie algebraic methods. Although approximate, we show that these models allow in particular to recover the possible ground state crossover when quadratic couplings are present. The equivalence of E x e and G' x e vibronic systems in cubic symmetry is precisely established through a particular realization of the electronic operators for an orbital quadruplet. We show how this equivalence is broken by a rovibronic interaction which, for a G' x e system, still gives an exactly solvable model.
Reference Type: Journal Article Author: Pashayan-Leroy, Y.; Leroy, C.; Sargsyan, A.; Papoyan, A.; Sarkisyan, D. Year: 2007 Title: Electromagnetically induced transparency: the thickness of the vapor column is of the order of a light wavelength Journal: Journal of the Optical Society of America B-Optical Physics Volume: 24 Issue: 8 Pages: 1829-1838 Abstract: Electromagnetically induced transparency (EIT) effect has been studied using an extremely thin cell (ETC) with the thickness of an Rb vapor column of the order of light wavelength lambda (780 nm) and varying in the range of 0.5 lambda-2.5 lambda. Lambda-systems on the D2 line of 85Rb and 87Rb have been studied experimentally. Along with EIT resonance, we study the peculiarities of velocity-selective optical pumping/saturation (VSOP) resonances, which accompany the EIT resonance and, as a rule, are spectrally broader. It is demonstrated that size-conditioned strongly anisotropic contribution of atoms with different velocities in an ETC causes several dramatic differences of the EIT and VSOP resonances formation in the ETC as compared with an ordinary 1-10 cm long cell. Particularly, in the case of the ETC, the EIT linewidth and contrast dramatically depend on the coupling laser detuning from the exact atomic transition. A theoretical model taking into account the peculiarities of transmission spectra when L = n lambda and L = (2n + 1)lambda/2 (n is an integer) has been developed. The experimental transmission spectra are well described by the theoretical model developed. The possibility of EIT resonance formation when atomic column thickness is of the order of L = 0.5 lambda and less is theoretically predicted. (c) 2007 Optical Society of America.
Reference Type: Journal Article Author: Negrao, A.; Coustenis, A.; Lellouch, E.; Maillard, J. P.; Rannou, P.; Schmitt, B.; McKay, C. P.; Boudon, V. Corporate Author Hrsc-Co-Investigator-Team Year: 2007 Title: Titan's surface albedo variations over a Titan season from near-infrared CFHT/FTS spectra (vol 54, pg 1225, 2006) Journal: Planetary and Space Science Volume: 55 Issue: 14 Pages: 2221 Abstract: Correction to previously published article.
Reference Type: Journal Article Author: Wenger, C.; Boudon, V.; Rotger, M.; Sanzharov, M.; Champion, J. P. Year: 2008 Title: XTDS and SPVIEW: Graphical tools for the analysis and simulation of high-resolution molecular spectra Journal: Journal of Molecular Spectroscopy Volume: 251 Issue: 1-2 Pages: 102-113 Abstract: XTDS is a Java front-end to the different programs implementing the tensorial formalism developed in the Dijon group (see for instance: V. Boudon, J.-P. Champion, T. Gabard, M. Loete, F. Michelot, G. Pierre, M. Rotger, Ch. Wenger, M. Rey, J. Mol. Spectrosc. 228 (2004) 620-634]. It allows the simulation and analysis of polyad systems for molecules of various symmetries (Td and Oh spherical tops like CH4 and SF6, C2v and C4v, quasi-spherical tops like SO2F2 and SF5Cl. D2h molecules like C2H4). SPVIEW is it multiplatform Java application that allows graphical assignment of high-resolution molecular spectra. It is possible to load, display and manipulate experimental and simulated spectra (XY ASCII format) as well as stick spectra in various formats (including HITRAN format). Lines can be assigned graphically using the mouse. Assignments can also be modified or removed. Local simulations can be performed in order, for instance, to help assignment in partly resolved line clusters. SPVIEW is also able to produce peak lists from an experimental spectrum. Both software can be freely downloaded at the URL http://icb.u-bourgogne.fr/OMR/SMA/SHTDS. (c) 2008 Elsevier Inc. All rights reserved. Reference Type: Journal Article Author: Asselin, P.; Soulard, P.; Boudon, V. Year: 2008 Title: Jet-cooled FTIR spectroscopy and analysis of the v5 C-O stretch fundamental of Ni(CO)4 Journal: Molecular Physics Volume: 106 Issue: 9-10 Pages: 1135-1141 Abstract: Rovibrational spectra of the C-O stretch band v5 of Ni(CO)4 have been recorded at 0.006 cm-1 resolution by coupling a low pressure continuous supersonic jet with a high resolution interferometer. The spectrum has been analysed thanks to the STDS software (see http://icb.u-bourgogne.fr/OMR/SMA/SHTDS/) that implements the tensorial formalism developed in the Dijon group for tetrahedral molecules. We obtain a very satisfying simulation thanks to an effective Hamiltonian expanded up to order 3. The asymmetry of the high-J lines is due to a small tetrahedral splitting and is well reproduced. The root mean square deviation is 0.96 x 10-3 cm-1. The Coriolis constant is somewhat larger than for other spherical-top carbonyls like Mo(CO)6 and W(CO)6 and, as a consequence, the level structure displays a standard three-branch structure, typical for triply degenerate fundamentals.
Reference Type: Journal Article Author: Boudon, V.; Di Lonardo, G.; Flaud, J. M.; Quack, M.; Softley, T. Year: 2008 Title: Twentieth colloquium on high resolution molecular spectroscopy - Dijon, 3 to 7 September 2007 - Foreword Journal: Molecular Physics Volume: 106 Issue: 9-10 Pages: 1125-1126 Abstract: Editorial material.
Reference Type: Journal Article Author: Niederer, H. M.; Albert, S.; Bauerecker, S.; Boudon, V.; Champion, J. P.; Quack, M. Year: 2008 Title: Global analysis of the infrared spectrum of 13CH4: Lines in the region 0 to 3200 cm-1 Journal: Chimia Volume: 62 Issue: 4 Pages: 273-276 Abstract: We have carried out new measurements of infrared spectra in a wide frequency range for the spherical top molecules 12CH4, 13CH4 and 12CD4 at low (80 K) and at room temperature (298 K). Spectra were recorded at very high resolution (0.0027 cm-1) for spectra in the region around 2900 cm-1, which corresponds to the pentad for 13CH4) using the Zurich prototype Bruker 125 spectrometer (ZP 2001) combined with a low temperature cooling cell and a White-type cell. At low temperature, the Doppler full line width at half maximum was reduced by a factor of 1.91 to 0.0045 cm-1 in the pentad region for 13CH4. We report the global analysis of 13CH4 transitions up to 3200 cm-1 and compare to previous work. In the present work line positions are reproduced with an rms deviation of 0.0004 cm-1. The complex interacting system is analyzed using the effective Hamiltonian approach elaborated in Dijon.
Reference Type: Journal Article Author: Rotger, M.; Boudon, V.; Auwera, J. V. Year: 2008 Title: Line positions and intensities in the v12 band of ethylene near 1450 cm-1: An experimental and theoretical study Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 109 Issue: 6 Pages: 952-962 Abstract: Recently, we built a tensorial formalism adapted to the spectroscopy of X2Y4 molecules. It is based on formalisms developed in Dijon for spherical-top molecules. This approach has the advantages to allow a systematic development of rovibrational interactions and to make global analyses easier to perform. We used this tool to carry out an analysis of the v12 band of 12C2H4 near 1450 cm-1, both in frequencies and intensities. 1240 line positions and 871 intensities, measured in a set of spectra recorded in Brussels, with global root mean square deviations of 1.6 x 10-4 cm-1 and 1.88%, respectively. (C) 2007 Elsevier Ltd. All rights reserved.
Reference Type: Journal Article Author: Thievin, J.; Georges, R.; Carles, S.; Benidar, A.; Rowe, B.; Champion, J. P. Year: 2008 Title: High-temperature emission spectroscopy of methane Journal: Journal of Quantitative Spectroscopy and Radiative Transfer Volume: 109 Issue: 11 Pages: 2027-2036
Abstract: A high-enthalpy source (HES) has been developed in Rennes either to heat gases up to 2000 K in local thermodynamic equilibrium (LTE) or to generate hypersonic expansions. The HES prototype has been associated with a high-resolution Bruker IFS 120 H R Fourier transform spectrometer to record emission spectra of hot gases, in LTE conditions. A series of emission spectra of methane has been obtained at 1005, 1365, 1485, 1625 and 1820 K in the pentad spectral region located around 3000 cm-1, at Doppler-limited resolution (0.02cm-1). Spectra have been corrected for the transmission function that strongly affects the infrared radiation emitted by the hot gas. Line-integrated absorption cross sections have been extracted from the corrected spectra using an improved procedure for the calculation of the total partition function Q of methane at high temperature. This calculation included anharmonicity and rovibrational interaction effects, and was based on a multi-resolution fully converged direct partition sum. It has been shown that, as the temperature increases above 1000 K, the commonly used harmonic and rigid rotor double approximation to estimate Q leads to underestimated values. (c) 2008 Elsevier Ltd. All rights reserved.
Reference Type: Journal Article Author: Antony, B. K.; Niles, D. L.; Wroblewski, S. B.; Humphrey, C. M.; Gabard, T.; Gamache, R. R. Year: 2008 Title: N2-, O2- and air-broadened half-widths and line shifts for transitions in the v3 band of methane in the 2726-to 3200-cm-1 spectral region Journal: Journal of Molecular Spectroscopy Volume: 251 Issue: 1-2 Pages: 268-281 Abstract: Complex Robert-Bonamy calculations of the pressure-broadened half-width and the pressure-induced line shift are made for some 4000 transitions in the v3 band of methane with N2, O2, and air as the perturbing gases. This work focuses on A and F symmetry transitions in the spectral range 2726 to 3200 cm-1. More work is needed on the intermolecular potential before calculations can be made for the E-symmetry transitions. The calculations are made at 225 and 296 K in order to determine the temperature dependence of the half-width. The calculations are compared with measurements. These data are to support remote sensing of the Earth and Titan atmospheres. (C) 2008 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Rey, M.; Michelot, F.; Tyuterev, V. G. Year: 2008 Title: Formalism of the displaced squeezed Fock states for variational calculations of highly excited ro-vibrational levels: Diatomic molecules - art. no. 022511 Journal: Physical Review A Volume: 78 (2) Part A Pages: 022511-1 - 022511-16 Abstract: A set of displaced squeezed number states is proposed as trial wave functions in variational calculations of ro-vibrational energy levels of diatomic molecules. By employing the ladder-operator formalism, we construct such states as well as an algebraic Hamiltonian expressed in terms of normal-ordered boson operators. We also show that this algebraic Hamiltonian can be expanded in terms of pseudoladder operators ã(lambda, kappa) and ã+(lambda, kappa) obtained via a generalized Bogoliubov transformation. In this case, the Hamiltonian matrix is built using the usual Fock basis set and the coherence and squeezing parameters lambda and kappa are optimized variationally. The convergence of the variational calculations is largely improved when using the displaced squeezed number states instead of the usual Fock ones. A class of generalized displaced squeezed number states is also considered, and some numerical applications are given.
Reference Type: Journal Article Author: Sanzharov, N. A.; Leroy, C.; Ulenikov, O. N.; Bekhtereva, E. S. Year: 2008 Title: On the study of the vibrational energy levels of arsine molecule Journal: Journal of Molecular Spectroscopy Volume: 247 Issue: 1 Pages: 1-24 Abstract: We compare two formalisms applied to the vibrational modes of the molecule of AsH3 of C3v molecular symmetry group. Indeed, the close stretching modes of this molecule may be considered as those of a three-dimensional oscillator whereas the bending modes may be considered either as a one-dimensional oscillator of symmetry A, and a two-dimensional oscillator of symmetry E or as ail approximate three-dimensional oscillator. So, we have applied the U(p + 1) formalism to the both stretching and bending modes and introduced coupling terms acting on an appropriate coupled vibrational basis through a local mode formalism. We have then compared the result of our fitting with those obtained with the coupling of a local mode formalism adapted to the stretching vibrations with a normal mode formalism for the bending ones. Finally we compare our results with other methods recently proposed in the literature. (c) 2007 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Wenger, C.; Champion, J. P.; Boudon, V. Year: 2008 Title: The partition sum of methane at high temperature Journal: Journal of Quantitative Spectroscopy & Radiative Transfer Volume: 109 Issue: 16 Pages: 2697-2706 Abstract: The total internal partition function of methane is revisited to provide reliable values at high temperature. A multi-resolution approach is used to perform a direct summation over all the rovibrational energy levels up to the dissociation limit. A computer code is executable on line at the URL: http://icb.u-bourgogne.fr/JSP/TIPS.jsp to allow the calculation of the partition sum of methane at temperatures up to 3000K. It also provides detailed information on the density of states in the relevant spectral ranges. The recommended values include uncertainty estimates. It is shown that at the upper limit of 3000 K, the systematic error (underestimation) of previous calculations (HITRAN 2004) reaches -50% equivalent to a temperature error of the order of +200 K. (C) 2008 Elsevier Ltd. All rights reserved.
Reference Type: Journal Article Author: Albert, S.; Bauerecker, S.; Boudon, V.; Brown, L. R.; Champion, J. P.; Loete, M.; Nikitin, A.; Quack, M. Year: 2009 Title: Global analysis of the high resolution infrared spectrum of methane 12CH4 in the region from 0 to 4800 cm-1 Journal: Chemical Physics Volume: 356 Issue: 1-3 Pages: 131-146 Abstract: We report the global analysis of methane (12CH4) lines from high resolution rovibrational spectra including accurate line positions and intensities in the region 0-4800 cm-1. This covers four polyads: The Ground State Monad (rotational levels), the Dyad (940-1850 cm-1, 2 vibrational levels, 2 sublevels), the Pentad (2150-3350 cm-1, 5 vibrational levels, 9 sublevels) and the Octad (3550-4800 cm-1, 8 vibrational levels, 24 sublevels) and some of the associated hot bands (Pentad-Dyad and Octad-Dyad). New Fourier transform infrared (FTIR) spectra of the Pentad and Octad regions have been recorded with a very high resolution (better than 0.001 cm-1 instrumental bandwidth, unapodized) at 78 K using the Bruker IFS 125 HR Zurich prototype (ZP2001) spectrometer in combination with a long optical path collisional cooling system [S. Albert, S. Bauerecker, M. Quack, A. Steinlin, Mol. Phys. 105 (2007) 541]. Existing spectra previously recorded with the FTIR spectrometer at the National Solar Observatory on Kitt Peak in Arizona were remeasured selectively to provide new intensities and positions of weaker lines above 4400 cm-1. These were combined with previously reported absorption data from MR and laser absorption, as well as high-resolution stimulated Raman and microwave spectra. The effective hamiltonian was expanded up to order 6 for the Ground State, order 6 for the Dyad, order 5 for the Pentad and order 5 for the Octad. A total of 16,738 line positions were used in the least squares adjustment characterized by the following global root mean square deviations dRMS for line positions: 1.3 x 10-4 cm-1 for the Dyad, 6.0 x 10-4 cm-1 for the Pentad, and 3.5 x 10-3 cm-1 for the Octad. Absolute intensities were also analyzed for all the cold bands and some of the hot bands in the region under consideration and we obtained dRMS = 9.6% including 3262 experimental line intensities for the Octad. This analysis represents a large improvement over the previous one [J.-C. Hilico, O. Robert, M. Loete, S. Toumi, A.S. Pine. L.R. Brown, J. Mol. Spectrosc. 208 (2001) 1] with dRMS = 0.041 cm-1 for positions and 15.6% for intensities in the Octad for a smaller data set. The new results are discussed as benchmarks in relation to accurate potential energy hypersurfaces and for atmospheric and planetary spectra. (C) 2008 Elsevier B.V. All rights reserved.
Reference Type: Journal Article Author: El Hilali, A.; Boudon, V.; Loete, M. Year: 2009 Title: Tensorial development of the rovibronic Hamiltonian and dipole moment operators for XY3Z molecules with a degenerate electronic state: Preliminary application to the CH3O radical Journal: Journal of Molecular Spectroscopy Volume: 253 Issue: 2 Pages: 92-98 Abstract: We present a development of the Hamiltonian and transition moment operators of XY3Z (C3v) symmetric tops molecules in a degenerate electronic state with the aid of a tensorial formalism developed in a recent paper [A. El Hilali, V. Boudon, M. Loete, J. Mol. Spectrosc. 239 (2006) 41-50]. Electronic operators are defined from group theory properties. They provide a new approach to build an effective rovibronic Hamiltonian as well as an effective dipole moment operator for rovibronic transition of XY3Z molecules. This model is studied qualitatively thanks to the tensorial algebra properties. Expressions of the matrix elements are derived for these operators. A first simple application to the ground electronic state of CH3O is proposed as an illustrative example. (C) 2008 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Grigoryan, G. G.; Nikoghosyan, G. V.; Halfmann, T.; Pashayan-Leroy, Y. T.; Leroy, C.; Guerin, S. Year: 2009 Title: Theory of the bright-state stimulated Raman adiabatic passage Journal: Physical Review A Volume: 80 Issue: 3 Pages: 9 Abstract: We describe analytically and numerically the process of population transfer by stimulated Raman adiabatic passage through a bright state when the pulses propagate in a medium. Limitations of the adiabaticity are analyzed and interpreted in terms of reshaping of the pulses. We find parameters for the pulses for which the population transfer is nearly complete over long distances.
Reference Type: Journal Article Author: Grigoryan, G. G.; Pashayan-Leroy, Y. T.; Leroy, C.; Guerin, S. Year: 2009 Title: Short-length storage of intense optical pulses in solids by adiabatic passage Journal: Physical Review A Volume: 79 Issue: 1 Pages: 6 Abstract: We propose a scheme of storage of intense pulses that allows a significant reduction of the storage length with respect to standard schemes. This scheme is particularly adapted to store optical information in media with fast relaxations.
Reference Type: Journal Article Author: Kalugina, Y. N.; Cherepanov, V. N.; Buldakov, M. A.; Zvereva-Loete, N.; Boudon, V. Year: 2009 Title: Theoretical investigation of the potential energy surface of the van der Waals complex CH4-N2 Journal: Journal of Chemical Physics Volume: 131 Issue: 13 Pages: 9 Abstract: The interaction potential energy surface of the van der Waals CH4-N2 complex has been calculated for a broad range of intermolecular separations and configurations in the approximation of rigid interacting molecules at the CCSD(T) and MP2 levels of theory using the correlation consistent aug-cc-pVTZ basis set. The BSSE correction was taken into account for all the calculations. The most stable configurations of the complex were found. Binding energies were calculated in the CBS limit with accounting for the molecular deformations. The harmonic and anharmonic fundamental vibrational frequencies and rotational constants for the ground and first excited vibrational states were calculated for the most stable configurations at the MP2 level of theory with BSSE correction. Fitting parameters were found for the most stable configuration for the Lennard-Jones and Esposti-Werner potentials. (C) 2009 American Institute of Physics. [doi:10.1063/1.3242080]
Reference Type: Journal Article Author: Lorono, M.; Bermejo, D.; Rotger, M.; Boudon, V. Year: 2009 Title: High-resolution stimulated Raman spectroscopy and analysis of the 2 nu(10) overtone symmetric motion of C2H4 Journal: Journal of Raman Spectroscopy Volume: 40 Issue: 8 Pages: 1065-1071 Abstract: The high-resolution stimulated Raman spectrum of the 2v10 band located at 1664.16 cm-1 of C2H4 has been reanalyzed, thanks to the tensorial formalism developed in Dijon for X2Y4 asymmetric-top molecules. A total of 191 lines were assigned and fitted as a single band without including perturbations such as Fermi or Coriolis coupling constants. We obtained a global root mean square deviation of 8.5 x 10-3 cm-1. Further investigations are required to include interactions with the v2 and v7 + v10 bands. Copyright (C) 2009 John Wiley & Sons, Ltd.
Reference Type: Journal Article Record Number: 4 Author: Margules, L.; Perrin, A.; Demaison, J.; Merke, I.; Willner, H.; Rotger, M.; Boudon, V. Year: 2009 Title: Breakdown of the reduction of the rovibrational Hamiltonian: The case of S18O2F2 Journal: Journal of Molecular Spectroscopy Volume: 256 Issue: 2 Pages: 232-237 Abstract: The ground state rotational spectrum of the near-spherical top molecule S18O2F2 (sulfuryl fluoride) has been measured from 50 to 700 GHz. As for the parent isotopologue, S16O2F2 [K. Sarka, J. Demaison, L Margules, I. Merke, N. Heineking, H. Burger, H. Ruland, J. Mol. Spectrosc. 200 (2000) 55-64], it was necessary to use a non-reduced Hamiltonian in order to obtain a satisfactory fit. It was possible to determine six quartic centrifugal distortion constants (instead of five for a standard asymmetric top) and five sextic constants (one of them not existing in the reduced Hamiltonian) could also be determined. This ground state level has also been analysed thanks to a tensorial formalism developed in Dijon. Only two tensorial sextic constants are fixed to zero, all others have been adjusted. Although S18O2F2 is less spherical than S16O2F2, the analysis was more difficult. It is partly due to the fact that S18O2F2 is oblate whereas S16O2F2 is prolate. The experimental quartic centrifugal distortion constants were found in good agreement with those calculated from the force field, confirming the correctness of the analysis. (C) 2009 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Rey, M.; Michelot, F. Year: 2009 Title: Matrix elements for powers of x-dependent operators for the hyperbolic Poschl-Teller potentials Journal: Journal of Physics a-Mathematical and Theoretical Volume: 42 Issue: 16 Pages: 20 Abstract: Analytical matrix elements of the position operator x(n) (n > 0) and of the first- and second-order differential operators are derived using the eigenfunctions of two hyperbolic Poschl-Teller potentials. These general relations are written in closed form and calculated from the properties of the integral powers of hypergeometric series. Additionally, an explicit expression is derived for the successive derivatives of the Beta function. Convergence and reliability of these results will be discussed and an application to the calculation of the rovibrational energy spectrum of CO will be considered.
Reference Type: Journal Article Author: Rothman, L. S.; Gordon, I. E.; Barbe, A.; Benner, D. C.; Bernath, P. E.; Birk, M.; Boudon, V.; Brown, L. R.; Campargue, A.; Champion, J. P.; Chance, K.; Coudert, L. H.; Dana, V.; Devi, V. M.; Fally, S.; Flaud, J. M.; Gamache, R. R.; Goldman, A.; Jacquemart, D.; Kleiner, I.; Lacome, N.; Lafferty, W. J.; Mandin, J. Y.; Massie, S. T.; Mikhailenko, S. N.; Miller, C. E.; Moazzen-Ahmadi, N.; Naumenko, O. V.; Nikitin, A. V.; Orphal, J.; Perevalov, V. I.; Perrin, A.; Predoi-Cross, A.; Rinsland, C. P.; Rotger, M.; Simeckova, M.; Smith, M. A. H.; Sung, K.; Tashkun, S. A.; Tennyson, J.; Toth, R. A.; Vandaele, A. C.; Vander Auwera, J. Year: 2009 Title: The HITRAN 2008 molecular spectroscopic database Journal: Journal of Quantitative Spectroscopy & Radiative Transfer Volume: 110 Issue: 9-10 Pages: 533-572 Abstract: This paper describes the status of the 2008 edition of the HITRAN molecular spectroscopic database. The new edition is the first official public release since the 2004 edition, although a number of crucial updates had been made available online since 2004. The HITRAN compilation consists of several components that serve as input for radiative-transfer calculation codes: individual line parameters for the microwave through visible spectra of molecules in the gas phase; absorption cross-sections for molecules having dense spectral features, i.e. spectra in which the individual lines are not resolved; individual line parameters and absorption cross-sections for bands in the ultraviolet; refractive indices of aerosols, tables and files of general properties associated with the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for 42 molecules including many of their isotopologues. (c) 2009 Elsevier Ltd. All rights reserved.
Reference Type: Journal Article Author: Ulenikov, O. N.; Bekhtereva, E. S.; Alanko, S.; Horneman, V. M.; Gromova, O. V.; Leroy, C. Year: 2009 Title: On the high resolution spectroscopy and intramolecular potential function of SO2 Journal: Journal of Molecular Spectroscopy Volume: 357 Issue: 2 Pages: 137-156 Abstract: Two weak stretching bands, v1 + 3v3 and 3v1 + v3, of the sulfur dioxide molecule have been recorded at high resolution and analyzed for the first time with using a Fourier transform Bruker IFS-120 HR interferometer.About 1000 transitions with Jmax = 51, Ka max = 16, and 900 transitions with Jmax = 53, Ka max = 16 have been assigned to the bands v1 + 3v3 and 3v1 + v3, respectively. Analysis of the recorded spectra was made using the model of isolated vibrational states. Parameters obtained from the fit reproduce the initial experimental ro-vibrational energies with the rms deviation of 0.0006 and 0.0012 cm-1 for the bands, 3v1 + v3 and v1 + 3v3, respectively. The problem of determination of the intramolecular potential function of SO2 is discussed. (C) 2009 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Ulenikov, O. N.; Bekhtereva, E. S.; Leroy, C. Title: On the local mode behaviour of the XH2/XD2 and XD/XH fragments with respect to the deuterated species of the near local mode XH3(C3v) molecule Journal: Molecular Physics Volume: 107 Issue: 14 Pages: 1409-1416 Abstract: Effect of isotopic substitution in the near local mode, XH3(C3v), molecules is considered. On that basis it is shown that the spectroscopic properties of deuterated and/or di-deuterated isotopic species of the XH3(C3v) molecule with the value of interbond angle close to π/2 are analogous to the spectroscopic properties of its separate fragments: of a three-atomic local mode 'molecule' XH2/XD2 and of a diatomic XD/XH 'molecule'. The phosphine molecule is considered as an illustration.
Reference Type: Journal Article Record Number: 12 Author: Ulenikov, O. N.; Bekhtereva, E. S.; Leroy, C.; Gromova, O. V.; Fomchenko, A. L. Year: 2009 Title: On the determination of the intramolecular potential energy surface of polyatomic molecules: Hydrogen sulfide and formaldehyde as an illustration Journal: Journal of Molecular Spectroscopy Volume: 255 Issue: 2 Pages: 88-100 Abstract: We present here an approach for determining the Hamiltonian of polyatomic molecules that allows one to successfully solve the problem of potential energy surface (PES) determination via construction and diagonalization of a Hamiltonian matrix of large dimension. In the suggested approach, the Hamiltonian is very simple and can be used both for any "normal" polyatomic molecule and for any isotopic species of a molecule. Molecules with two to four equivalent X-Y bonds are considered, and for illustration of the efficiency of the suggested approach, numerical calculations are made for the three-atomic (hydrogen sulfide) and four-atomic (formaldehyde) molecules. (C) 2009 Elsevier Inc. All rights reserved.
Reference Type: Journal Article Author: Zvereva-Loete, N.; Ballandras, A.; Weber, G.; Rotger, M.; Boudon, V.; Simon, J. M. Year: 2009 Title: Experimental IR study and ab initio modelling of ethylene adsorption in a MFI-type host zeolite Journal: Molecular Physics Volume: 107 Issue: 19 Pages: 2081-2093 Abstract: Different ab initio methods and experimental results are used to investigate the effect of the adsorption of one ethylene molecule on silicalite-1, a MFI-type zeolite. We used simplified models to simulate a portion of a straight or sinusoidal channel of silicalite-1 at a quantum level. The calculated absorption spectra of the models are qualitatively in good agreement with the experimental FTIR spectrum of silicalite-1. Additionally we simulate the FTIR spectrum of the isolated ethylene molecule and that of an ethylene molecule in interaction with the above-mentioned zeolite models. Results are discussed depending on the method and specific basis set and compared with experiments and previous molecular dynamics simulations.
Oh 
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CI representations in cubic point groups (Oh, Td) for application to molecular spectroscopy