Reduced effective Hamiltonian for Coriolis-interacting νn and νt fundamentals of C3v molecules

Lobodenko, E. I.; Sulakshina, O. N.; Perevalov, V.I.; Tyuterev, Vladimir G.

doi:10.1016/0022-2852(87)90086-5

Cited by 98 publications

(89 citation statements)

References 10 publications

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“…Of course not all the 1139 eective hamiltonian terms can be adjusted simultaneously. The main reason is that, given a set of hamiltonian eigenvalues, there exist in principle an innite number of equivalent sets of eective parameters corresponding to various forms of reduced hamiltonians [31]. This is already true for isolated band models and more pronounced in the case of a polyad adapted model.…”

Section: C3vmentioning

confidence: 99%

Global modeling of the lower three polyads of PH3: Preliminary results

Nikitin

Champion

Butler

et al. 2009

Journal of Molecular Spectroscopy

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In order to model the high-resolution infrared spectrum of the phosphine molecule in the 3 µm region, a global approach involving the lower three polyads of the molecule (Dyad, Pentad and Octad) as been applied using an eective hamiltonian in the form of irreducible tensors. This model allowed to describe all the 15 vibrational states involved and to consider explicitly all relevant ro-vibrational interactions that cannot be accounted for by conventional perturbation approaches.2245 levels (up to J = 14) observed through transitions arising from 34 cold and hot bands including all available existing data as well as new experimental data have been tted simultaneously using a unique set of eective hamiltonian parameters.The rms achieved is 0.63 × 10 µm by dividing the rms reported by previous works by a factor 6. A preliminary intensity analysis based on consistent sets of eective dipole moment operators for cold and hot bands has been simultaneously undertaken for direct comparison between observed and modeled absorption from 700 to 3500 cm −1 .Keywords : Phosphine ; PH 3 ; Vibrational polyads ; Global modeling ; Near infrared ; High-resolution ; Positions ; Intensities IntroductionAs part of extensive eorts to support remote sensing of Jupiter and Saturn many works have been devoted to the high-resolution infrared spectrum of phosphine [1,2,3, 4, 5, 6, 7]. Recent works focused on the 3 µm region reported experimental measurements and assignments [5, 7], but so far no comprehensive modeling was reported.1 hal-00355701, version 1 -23 Jan 2009 At present, the line parameters of phosphine (positions and intensities) in the 3 µm region rely essentially on the empirical database reported in Ref. [7] and included in HITRAN [8] and GEISA [9]. In the spectral region from 2700 to 3500 cm −1 , the HITRAN compilation contains over 3000 unassigned PH 3 lines with intensities ranging from 1. × 10 −25 to 1.5 × 10 −22 cm×molecule −1 . Moreover, only one hot band arising from the upper state of ν 2 is included. The main reason for this lack of modeling is the fundamental limitation of conventional perturbation approaches. So far, only weakly interacting features could be tted using isolated band models while strongly interacting states were left out. In fact, apart from degeneracy considerations, due to the quasi spherical character of the inertia tensor of the molecule and to specic quasi coincidences among its vibrational fundamental frequencies, the vibrational pattern of the phosphine molecule is quite similar to that of the methane molecule. The phosphine molecule was then a good candidate for the global approach successfully developed for spherical tops [10,11] and extensively applied to other complex band systems encountered in polyatomic molecules [12,13,14]. The vibrational spectrum of PH 3 and its isotopomers has also been investigated by ab initio calculations [15,16,17,18]. Recent works have reported ab initio vibrational energies [19,20] and theoretical transition moments [21]. The experimental data involv...

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Section: C3vmentioning

confidence: 99%

Global modeling of the lower three polyads of PH3: Preliminary results

Nikitin

Champion

Butler

et al. 2009

Journal of Molecular Spectroscopy

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“…Statistical correlations arise not only from possible deciencies of the coverage by experimental data but also from essential colinearities in eective hamiltonians [15,14,16]. To help selecting adjustable parameters at any stage of the iterative assignment procedure special options of MIRS allow to run series of iterations with automatic introduction of new parameters or elimination of statistically unsignicant parameters among pre-selected terms specied by the user.…”

Section: Advanced Features For Spectroscopic Non-linear Least-squaresmentioning

confidence: 99%

The MIRS computer package for modeling the rovibrational spectra of polyatomic molecules

Nikitin

Champion

Tyuterev

2003

Journal of Quantitative Spectroscopy and Radiative Transfer

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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 ecient algorithms based on the irreducible tensor formalism. Predictions and simultaneous data tting (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

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“…Of the A 1 states the ground (7) and the v 3 ϭ 1 states (9) of DSiF 3 were also found to be unperturbed. An A 1 A 2 splitting of K ϭ 3 rotational levels of the ground state accounted for by an off-diagonal parameter h 3 was revealed for sufficiently high J values.…”

Section: Introductionmentioning

confidence: 96%

“…HSiF 3 and DSiF 3 have recently attracted new interest as prototype molecules to test the applicability of different reductions of the rovibrational Hamiltonian to oblate symmetric-top molecules (1-3), and both experimental (high-resolution IR, microwave (MW) and millimeter-wave (MMW)) (4 -7) and theoretical studies (8) have been performed with that task.…”

Section: Introductionmentioning

confidence: 99%