Diode laser spectroscopy of the nu(8) band of the SF(5)Cl molecule.

Abstract Diode laser spectra of SF 5 Cl have been recorded in the ν 8 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 ν 1 / ν 8 dyad of SF 5 35 Cl 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 refi…

Effect of the Zeolite Framework on Spectroscopic Properties of Ethylene: FTIR Measurements and Quantum Chemical Calculations

Intensity Analysis of the 10 Micron Band System of Ethylene

High-Resolution Spectroscopy and Preliminary Analysis of the ν1/ν8 Dyad of SF535Cl

Abstract The Fourier transform infrared spectrum of monoisotopic SF 5 35 Cl 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 ν 1 /ν 8 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 C 4 v TDS ( C 4 v Top Data System, http://www.u-bourgogne.fr/LPUB/C4VTDS.html ); 1346 transitions for ν 1 , 351 transitions for ν 8 , 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 ν 1 ( a 1 ) band, of 0.…

The SO2F2 quasi-spherical top: Correspondence between tensorial and Watson's formalisms

Abstract The SO2F2 quasi-spherical top molecule with C2v symmetry is considered as a distorted spherical top deriving from the SO 4 2 − tetrahedral ion. We present here a detailed correspondence between the tensorial formalism using the Td⊃C2v 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.

MeCaSDa and ECaSDa: Methane and ethene calculated spectroscopic databases for the virtual atomic and molecular data centre

Abstract Two spectroscopic relational databases, denoted MeCaSDa and ECaSDa, have been implemented for methane and ethene, and included in VAMDC (Virtual Atomic and Molecular Data Centre, http://portal.vamdc.eu/vamdc_portal/home.seam ). These databases collect calculated spectroscopic data from the accurate analyses previously performed for the electronic ground state of methane, ethene, and some of their isotopologues: 12CH4, 13CH4, and 12C2H4. Both infrared absorption and Raman scattering lines are included. The polyad structures are reported and the transitions are precisely described by their energy, their intensity and the full description of the lower and upper states involved in the …

Experimental IR Study and Ab Initio Modelling of Ethylene Adsorption in a MFI Zeolite-Type Host Zeolite

International audience

High-Resolution Spectroscopy and Preliminary Global Analysis of C–H Stretching Vibrations of C2H4 in the 3000 and 6000 cm-1 Regions

International audience; Ethylene (ethene, H2C=CH2) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C2H4 spectrum is available in databases only for the 1000 and 3000 cm−1 ranges. In this work, the ethylene absorption spectrum was measured in the 6030- 6250 cm−1 range with the use of a high resolution Bruker IFS 125HR Fourierspectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases. A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software…

Stark Effect Using Tensorial Formalism in the D2h Group: Application to the C2H4 Molecule

Line Positions and Intensities in the ν12 Band of Ethylene Near 1450 cm-1: An Experimental and Theoretical study

International audience

The ground state rotational spectrum of SO2F2

Abstract The analysis of the ground state rotational spectrum of SO 2 F 2 [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 SO 2 F 2 is a quasi-spherical top, it can also be regarded as derived from an hypothetical XY 4 molecule. Thus we have developed a new tensorial formalism in the O (3)⊃ T d ⊃ C 2 v 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). Bot…

High-Resolution Ethylene Absorption Spectrum Between 6035 and 6210 cm-1

top data system ( TDS) software for infrared spectrum simulation of asymmetric molecules: some improvements to the TDS packages

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 XY 2 Z 2 ( C 2 v ) asymmetric top molecules. We work in the O ( 3 ) ⊃ T d ⊃ C 2 v 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 quasi-spherical molecule is presented. As before, this suite con…

Stimulated Raman and Cars Spectroscopy of ν1 and 2ν2 (A1) Bands of 12CF4

Two experimental coherent Raman techniques, stimulated Raman and coherent anti-Stokes Raman spectroscopy (CARS), were employed to study the Raman spectrum of CF 4 in the 900 cm −1 region. The stimulated Raman and CARS spectra of the ν 1 band of CF 4 were recorded at high resolution. The analysis of these spectra enabled some spectroscopic constants of this band to be refined and higher order constants to be determined for the first time. The first high-resolution CARS spectrum of the 2ν 2 (A 1 ) harmonic band is also presented. The rotational transitions of this band up to J = 40 were assigned and the first set of spectroscopic constants for this sub-level were determined. These results imp…

Spectroscopy of XY5Z (C4v) Molecules: A Tensorial Formalism Adapted to the O(3) ⊃ Oh ⊃ C4v Chain

Abstract A tensorial formalism adapted to the case of XY 5 Z symmetric tops has been developed as an extension of the usual one for the octahedral molecules. We use the O (3) ⊃ O h ⊃ C 4 v 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 C 4 v group itself.

Spectroscopy of XY5Z (C4v) Molecules: Development of the Hamiltonian and the Transition Moment Operators Using a Tensorial Formalism

We present a development of the Hamiltonian, dipole moment, and polarizability operators of XY(5)Z (C(4v)) molecules using a tensorial formalism derived from the one developed previously in Dijon for XY(6) 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. Copyright 2000 Academic Press.

Symmetry-adapted tensorial formalism to model rovibrational and rovibronic spectra of molecules pertaining to various point groups

International audience; 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 rovib- rational/rovibronic probl…

Analyse du Spectre de l'Ethylene dans la Région 800–1500 cm-1 à l'Aide du Formalisme Tensoriel : Fréquences et Intensités

D2hTDS-ST Software for Stark Spectrum Simulation of X2Y4 Asymmetric-Top Molecules

Abstract We present the D 2 h TDS-ST ( D 2 h -Top Data System for Stark effect) program suite with the aim to simulate Stark spectra of any IR active rovibrational polyad of X 2 Y 4 ( D 2 h ) asymmetric-top molecules. D 2 h TDS-ST consists in a series of FORTRAN programs called by scripts. For calculation of Stark spectra, we obtained the expressions of the dipole moment and polarizability operators of X 2 Y 4 molecules using a tensorial formalism. For convenience, we integrated the D 2 h TDS-ST programs into the D 2 h TDS package. The D 2 h TDS suite (including the D 2 h TDS-ST programs) is freely available at the URL: http://icb.u-bourgogne.fr/OMR/SMA/SHTDS/D2HTDS.html .

Spectroscopy of X2Y4 (D2h) molecules: tensorial formalism adapted to the O(3)⊃D2h chain, Hamiltonian and transition moment operators

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.

The 2009 Edition of the GEISA Spectroscopic Database

The updated 2009 edition of the spectroscopic database GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques; Management and Study of Atmospheric Spectroscopic Information) is described in this paper. GEISA is a computer-accessible system comprising three independent sub-databases devoted, respectively, to: line parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols. In this edition, 50 molecules are involved in the line parameters sub-database, including 111 isotopologues, for a total of 3,807,997 entries, in the spectral range from 10-6 to 35,877.031cm-1.The successful performances of the new …

Analysis of the Spectrum of Ethylene in the 800–1500 cm-1 Region Using Tensorial Formalism: Frequencies and Intensities

Stark Spectrum Simulation of X2Y4 Asymmetric Molecules: Application to Ethylene in a MFI-Type Host Zeolithe

Corrigendum to “Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2h top data system” [J. Quant. Spectrosc. Radiat. Transf. 182 (2016) 158–171]

Abstract This corrigendum provides a new version of one of the 3 supplementary data files associated with the article A. Alkadrou et al., J. Quant. Spectrosc. Radiat. Transf. 182 (2016) 158–171, namely the HITRAN-formatted linelist generated as described in section 5 of the article. Indeed, the K a and K c labels of the upper levels of a number of transitions belonging to the ν 10 , ν 7 and ν 4 bands listed in this supplementary data file were found to be incorrect. The linelist provided with this corrigendum corrects these erroneous assignments, and provides K a and K c labels for all the upper levels.

Self-broadening coefficients and improved line intensities for the ν7 band of ethylene near 10.5μm, and impact on ethylene retrievals from Jungfraujoch solar spectra

Relying on high-resolution Fourier transform infrared (FTIR) spectra, the present work involved extensive measurements of individual line intensities and self-broadening coefficients for the ν7 band of 12C2H4. The measured self-broadening coefficients exhibit a dependence on both J and Ka. Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database, the measured line intensities were found to be higher by about 10% for high J lines in the P branch and lower by about 5% for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. The impact of the presently measured line intensities on retrieva…

Simulation du Spectre Stark des Molécules X2Y4 : Application à l'Ethylène dans les Zéolithes

The bending triad of the quasi-spherical top molecule SO2F2 in the 550 cm(-1) region

International audience; The analysis of the v(3)/v(7)/v(9) 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) > Td > C2v group chain [M. Rotger, V. Boudon, M. Loete, J. Mol. Spectrosc. 216 (2002) 297-307]. This approach allows a systematic development of rovibra…

From the spherical top to the asymmetric top

This habilitation report presents a synthesis of my research work during the last 14 years. I have distinguished my experimental activities (part III), my theoretical work on the spectroscopy of quasi-spherical tops (part IV) and that concerning the spectroscopy of molecules trapped in solids (part V).

XTDS and SPVIEW: Graphical tools for the analysis and simulation of high-resolution molecular spectra

International audience; 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. Loëte, 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 a multiplatform Java application that allows graphical assignment of high-resolution molecular spectra. It is possible to load, display and manipulate experimental and …

High-resolution spectroscopy of the ν3 band of WF6 and ReF6 in a supersonic jet

We have recorded the Fourier-transform infrared (FTIR) spectrum of the ν3 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. Che…

Infrared Spectroscopy of Molecules Trapped in Zeolites

C4v Top Data System (C4v TDS) software for infrared spectrum simulation of XY5Z symmetric molecules

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)⊃Oh⊃C4v 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 ν1/ν8 dyad of the SF 5 35 Cl molecule is presented. As before, this suite consists of a series of F…

Spontaneous Raman Scattering Spectrum of Gaseous IrF6 in the Ground Electronic State

Spectroscopy of Hexafluorides with an Odd Number of Electrons: The Vibronic Bands of IrF6

Abstract The low resolution absorption spectroscopy of the first five excited electronic states of IrF 6 has made possible some new assignments for the vibronic transitions of this molecule, and the determination of new vibronic parameter values. They are more accurate than those found in the literature. In this aim, we introduce a simplified tensorial formulation for the linear Jahn–Teller terms in a fourfold degenerate electronic state of an XY 6 -type molecule, which allows easier computation of matrix elements and avoids the use of perturbation theory. Methods for IrF 6 synthesis (using a dynamical flow system) and purification are also presented.

High-resolution spectroscopy and preliminary global analysis of C–H stretching vibrations of C2H4 in the 3000 and 6000cm−1 regions

Abstract Ethylene (ethene, H2C=CH2) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C2H4 spectrum is available in databases only for the 1000 and 3000 cm−1 ranges. In this work, the ethylene absorption spectrum was measured in the 6030–6250 cm−1 range with the use of a high resolution Bruker IFS 125HR Fourier-spectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases. A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software package [39] .…

Line positions and intensities in the band of ethylene near : An experimental and theoretical study

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 ν 12 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 × 10 - 4 cm - 1 and 1.88 % , respectively.

Measurements and Analysis of High Resolution Absorption Spectra of Ethylene within 5550 – 6300 cm-1

Communication: Evidence of structural phase transitions in silicalite-1 by infrared spectroscopy

The adsorption of trichloroethylene, perchloroethylene, and p-xylene on a MFI (Mobile-FIve) zeolite is studied using in situ FTIR spectroscopy at 298 K. Spectra of self-supported zeolites in contact with increasing pressures of pure gas were recorded at equilibrium in the mid-infrared domain. Analysis of the evolution of the shape and location of vibrational bands of the zeolite as a function of the amount adsorbed allowed the observation of structural modifications of the adsorbent for the first time by infrared spectroscopy.

Absorption spectrum of the f(A1g) ← X(Eg), a(F2g) electronic transition of OsF6

Abstract The absorption spectrum of the visible band of OsF 6 has been recorded using a commercial spectrophotometer. The first vibronic assignments for this band have been realized using the analogy with the d ← X transition of IrF 6 . Some vibronic parameter values are derived.

Simulation de l'Effet Stark dans la Bande ν12 de l'Ethylène

Absorption spectrum of the and electronic transitions of ReF6

Abstract The absorption spectra of the near-infrared and ultraviolet bands of ReF6 have been recorded with a commercial spectrophotometer. The vibronic assignments previously published by different authors are critically revised. A non-perturbative method has been used to calculate the linear Jahn–Teller levels for the ν5 mode in the ground electronic state. Some new vibronic parameter values are derived. The ν5 linear Jahn–Teller parameter in the X G′ g electronic state is found to be D5=0.103(9). The ultraviolet absorption spectrum has enabled us to determine relatively accurate values of the crystal-field (10Dq) and spin-orbit (ζd) parameters.

Ab InitioCalculations and High-Resolution Spectroscopy of the Bending Pentad of SiH2D2in the 10–16 μm Region

Abstract The SiH 2 D 2 asymmetric top has nine vibrational modes, five of them forming a pentad strongly perturbed by Coriolis interactions. High-level ab initio calculations of SiH 2 D 2 have been performed which yield numerous spectroscopic parameters related to the harmonic and anharmonic force fields. The bending pentad comprising ν 4 (A 1 ), ν 7 (B 1 ), ν 5 (A 2 ), ν 9 (B 2 ), and ν 3 (A 1 ) has been studied by high-resolution Fourier transform spectroscopy; the region 600–1050 cm −1 has been investigated with a resolution of ca. 4 × 10 −3 cm −1 . Raman BOXCARS spectroscopy has been used for the infrared inactive ν 5 band. The Raman apparatus function was 0.0054 cm −1 . Assignments of …

Spectroscopy of XY2Z2 (C2v) Molecules: A Tensorial Formalism Adapted to the O(3)⊃Td⊃C2v Chain. Application to the Ground State of SO2F2

Abstract A tensorial formalism adapted to the case of quasi-spherical XY 2 Z 2 asymmetric tops such as SO 2 F 2 has been developed as an extension of the usual one for the tetrahedral molecules. We use the O (3)⊃ T d ⊃ C 2 v 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 C 2 v 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 …

Spherical Top Theory and Molecular Spectra

In this article, we present an overview of the present state of the art of the theory of high-resolution spherical-top spectra in the framework of the effective Hamiltonian approach. We describe the specific features of this class of molecules to explain the basic concepts of the theoretical methods used for the analysis (line positions and intensities) and the simulation of absorption (including pure rotation) and Raman spectra of such species. The non conventional formalism that we use is essentially based on irreducible tensor methods and is especially adapted to computational treatments and global analyses of complex interacting band systems. We give examples concerning mainly methane (…

Analyse en Fréquence et en Intensité des Bandes de l'Ethylène à 10 Microns

top data system (TDS) software for spectrum simulation of asymmetric molecules

Abstract The D 2 h TDS ( D 2 h Top Data System) program suite has been developed with the aim of studying any rovibrational band or polyad of X 2 Y 4 ( D 2 h ) asymmetric top molecules. It is based on the same principles as similar programs from our group already released for various molecular symmetries ( T d , O h , C 4 v , C 2 v ). We work in the O ( 3 ) ⊃ D 2 h 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 ν 12 and ν 2 bands of the C 2 H 4 molecule are presented. This suite consists of a series of FORTRAN programs called by a script. The whole packa…

VAMDC: Databases of Calculated Spectral Lines of Ethylene and Methane

Breakdown of the Reduction of the Rovibrational Hamiltonian: The Case of S18O2F2

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 forma…

Experimental IR study and ab initio modelling of ethylene adsorption in a MFI - type host zeolite.

International audience; 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 wi…

Experimental Study and Ab Initio Modelling of the Ethylene Adsorption in a MFI-Type Host Zeolite

High‐resolution stimulated Raman spectroscopy and analysis of line positions and assignments for the ν 2 and ν 3 bands of 13 C 2 H 4

High-resolution stimulated Raman spectra of13C2H4 in the regions of the ν2 and ν3 Raman active modes have been recorded at two temperatures (145 and 296 K) based on the quasi continuous-wave (cw) stimulated Raman spectrometer at Instituto de Estructura de la Materia IEM-CSIC in Madrid. A tensorial formalism adapted to X2Y4 planar asymmetric tops with D2h symmetry (developed in Dijon) and a program suite called D2hTDS (now part of the XTDS/SPVIEW spectroscopic software) were proposed to analyze and calculate the high-resolution spectra. A total of 103 and 51 lines corresponding to ν2 and ν3 Raman active modes have been assigned and fitted in wavenumber with a global root mean square deviatio…

High-resolution spectroscopy and analysis of the ν4 band of 80SeF6

Abstract The Fourier-transform spectrum of the ν4 bending region of 80 SeF 6 around 435 cm −1 has been recorded at a temperature of 217 K with a resolution of 2.3×10 −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 ν4 band center is located at 435.099 cm −1 .