Search results for "spectroscopic parameters"
showing 8 items of 8 documents
Etude théorique de spectres de molécules toupies sphériques à l'aide du formalisme d'ensembles tensoriels irréductibles
2022
Vibrational-rotational spectroscopy of molecules of the spherical top type, in particular, SiH4 and GeH4 molecules, as well as their isotopologues, is of interest in various fields of science and technology, especially in astrophysics and planetology. One of the most important discoveries in the study of the atmospheres of giant planets is the discovery of german and silane gases in the atmospheres of Saturn, Titan, and Jupiter. Despite many years of research on the vibrational-rotational spectra of molecules of german, silane, and their deuterated modifications, many spectral ranges are still unexplored. However, a complete study of the atmospheres of giant planets is possible only in the …
On the Study of Resonance Interactions and Splittings in the PH3 Molecule: ν1, ν3, ν2+ν4, and 2ν4 Bands
2002
International audience; 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, ν1 and ν3. The ν2 + ν4 and 2ν4 bands are taken into account also. Experimental transitions are assigned to the ν1, ν3, ν2 + ν4, and 2ν4 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
High resolution study of AsHD2: Ground state and the three bending fundamental bands v(3), v(4), and v(6)
2006
International audience; For the first time the infrared spectrum of the AsHD2 molecule has been measured in the region of the bending fundamental bands v(3), v(4), and v(6) on a Fourier transform spectrometer with a resolution of 0.0024 cm(-1) and analyzed. More than 5500 transitions with J(max) = 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 …
High-resolution study of some doubly excited vibrational states of PH2D: the m1 + m2, m2 + m5, m2 + m3, and m2 + m6 bands
2004
Abstract The absorption bands ν 1 + ν 2 , ν 2 + ν 3 , and ν 2 + ν 6 of PH 2 D 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 ν 2 + ν 5 and enhanced in intensity by strong interactions with the ν 1 + ν 2 band were also assigned. Sets of parameters obtained from the fit reproduce experimental line position of the bands ν 1 + ν 2 and ν 2 + ν 3 with about the experimental accuracy. The residuals of the ro-vibrational energies of the ν 2 + ν 6 band are about 10 times larger. Reasons for the poorer reproduction of the latter data are given.
On the high resolution spectroscopy and intramolecular potential function of SO2
2009
Abstract Two weak stretching bands, ν 1 + 3 ν 3 and 3 ν 1 + ν 3 , 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 J max . = 51, K a max . = 16 , and 900 transitions with J max . = 53, K a max . = 16 have been assigned to the bands ν 1 + 3 ν 3 and 3 ν 1 + ν 3 , 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, 3 ν 1 + ν 3 and ν 1 …
High resolution study of the six lowest doubly excited vibrational states of PH2D
2005
Abstract The five lowest doubly excited deformational vibrational bands ν 4 + ν 6 , 2 ν 6 , ν 3 + ν 4 , ν 3 + ν 6 , and 2 ν 3 of PH 2 D 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 2 ν 4 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 .
Analysis of highly excited 'hot' bands in the SO2 molecule: ν2 + 3ν3 - ν2 and 2ν1 + ν2 + ν3 - ν2
2010
International audience; We set up a variational procedure of assignments of transitions and we applied it to the analysis very weak 'hot' bands, v(2) + 3v(3) - v(2) and 2v(1) + v(2) + v(3) - v(2), of the SO2 molecule. As the first step of the study, the 'cold' bands, 3v(3) and 2v(1) + v(3), are re-analysed and transitions belonging to those bands are assigned up to the values of quantum numbers J(max.) = 60, K-a(max.) = 19, and J(max.) = 69, K-a(max.) = 20 for the bands 3v(3) and 2v(1) + v(3), respectively. After 'cleaning' the experimental spectrum from transitions belonging to the 3v(3) and 2v(1) + v(3) bands, a variational procedure was used that allowed us to assign 230 and 115 transiti…
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
2009
International audience; 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.