AB INITIO AND EXPERIMENTAL STUDIES OF THE E INTERNAL ROTOR STATE OF He-CH$_3$F
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Date
2005
Journal Title
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Publisher
Ohio State University
Abstract
The excited {\it E} internal rotor state of He-CH$_3$F is studied using microwave spectroscopy and {\it ab initio} calculations. Bound state calculations on a high-level {\it ab initio} intermolecular potential surface} predict a T-shaped ground state and two low-lying excited states with the He localized either at the C end (``linear'') or the F end (``anti-linear'') of the C-F bond, similar to that found for the {\it A} internal rotor state presented previously.} There are several distinct differences between the {\it A} and {\it E} states. Whereas the ground state rotational transitions of the {\it A} state could be fit with a standard asymmetric rotor Hamiltonian, the {\it E} state exhibits a much more complex energy level structure due to the internal rotation of the CH$_3$F. In addition, the {\it E} state is calculated to be bound by 11.709 \wn, 0.249 \wn greater than the {\it A} state relative to their respective dissociation products, {\it K} = 1 or {\it K} = 0 CH$_3$F, and the ground state to linear state energy gap is predicted to be 4.148 \wn, 0.156 \wn greater than in the {\it A} state. At present six rotational transitions between five different energy levels have been observed and assigned with the aid of double resonance experiments and the {\it ab initio} calculations.
Description
{54th International Symposium on Molecular Spectroscopy (1999){55th International Symposium on Molecular Spectroscopy (2000)
Author Institution: Department of Chemistry and Chemical Biology, Harvard University,; Cambridge, Massachusetts 02138
Author Institution: Department of Chemistry and Chemical Biology, Harvard University,; Cambridge, Massachusetts 02138