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Proceedings Paper

Unusual vibrational predissociation dynamics of aromatic clusters with internal rotation
Author(s): Charles S. Parmenter; ZhongQuan Zhao
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Paper Abstract

A broad picture is emerging of the role played by methyl internal rotation on intramolecular vibrational redistribution (IVR) among ring modes of the benzene ring and on IVR between the ring modes and the van der Waals modes of complexes. The studies are based on the benchmark system p-difluorobenzene (pDFB) for which IVR at 300 K from many excited electronic state initial levels has been characterized long ago by oxygen quenching (chemical timing) of fluorescence. Replacement of a fluorine with a methyl group to make p- fluorotoluene (pFT) provides the methyl internal rotation that has strong interaction with the ring. A view of the methyl rotor effect on vibrational predissociation (VP) is obtained by studies of van der Waals complexes between these aromatics and Ar. The VP characteristics are qualitatively changed when a methyl internal rotation is introduced onto the ring. VP from lower initial levels of the pFT complex loses the high vibrational channel selectivity that is the signature of all other aromatic complexes. Those changes are traced back to an IVR process involving both ring modes and van der Waals modes that precedes the dissociation.

Paper Details

Date Published: 18 September 1995
PDF: 7 pages
Proc. SPIE 2548, Laser Techniques for State-Selected and State-to-State Chemistry III, (18 September 1995); doi: 10.1117/12.220845
Show Author Affiliations
Charles S. Parmenter, Indiana Univ. (United States)
ZhongQuan Zhao, ThermoTrex Corp. (United States)

Published in SPIE Proceedings Vol. 2548:
Laser Techniques for State-Selected and State-to-State Chemistry III
John W. Hepburn, Editor(s)

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