Dynamics of intramolecular vibrational-energy redistribution (IVR). III. Role of molecular rotations
Experimental results on jet-cooled anthracene pertaining to the role of rotations in IVR processes are presented. For theoretical comparison, we consider the effects of molecular rotational level structure on the beat-modulated decays that arise as manifestations of IVR. It is shown theoretically for anharmonic coupling that small differences in rotational constants between coupled vibrational states give rise to decays, the beat envelopes of which decay faster than the unmodulated portions of the decays. These envelope decay rates are shown to be rotational temperature dependent. The experimental results reveal behavior entirely consistent with the theoretical expectations. The results also show that although rotational effects are present in experimental decays, they are not so marked as to wash out the manifestations of vibrational coherence.
Additional Information© 1985 American Institute of Physics. Received 9 November 1984; accepted 17 December 1984. This work was supported by the National Science Foundation through Grant No. DMR-8105034. [P.M.F. was an] IBM Graduate Fellow. [A.H.Z. was a] Camille and Henry Dreyfus Foundation Teacher-Scholar. Arthur Amos Noyes Laboratory of Chemical Physics, Contribution No. 7118.
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