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Treatment of nonadiabatic interactions in polyatomic molecules by the frame transformation method: Application to the methyl iodide spectrum
Author(s) -
Dagata J. A.,
McGlynn S. P.
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560280831
Subject(s) - polyatomic ion , rydberg formula , chemistry , methyl iodide , degenerate energy levels , atomic physics , wave function , molecule , rydberg state , quantum defect , angular momentum , ion , molecular physics , physics , quantum mechanics , ionization , organic chemistry , medicinal chemistry
The frame transformation for an s ‐wave electron in the field of a degenerate symmetric top molecular ion core is used to interpret the results of a series of rotational bandshape fittings of one‐ and two‐photon absorption spectra of methyl iodide in the region of the lowest Rydberg transitions. The frame transformation is defined between alternative representations of the total wavefunction in which the spin of the Rydberg electron is successively decoupled from the molecular frame to the laboratory frame. It is shown that uncoupling of the spin from the molecular axis is essentially complete in the 6 s states of CH 3 I. Calculations are also presented which indicate that the dynamic Jahn‐Teller interaction leds to substantial angular momentum quenching in some vibronic levels of this molecule.