Show simple item record

dc.creatorGilbert, B. D.en_US
dc.creatorZhao, Z. Q.en_US
dc.creatorParmenter, C. S.en_US
dc.descriptionAuthor Institution: Department of Chemistry, Indiana University; JILA, Campus Box 440, University of Coloradoen_US
dc.description.abstractIt is well established from room temperature bulb studies that internal rotation of the methyl group in p-fluorotoluene (pFT) has a profound effect on the rate of intramolecular vibrational energy redistribution (IVR), especially when compared to a system such as p-difluorobenzene (pDFB), which lacks this extra degree of freedom provided by the rotor. Further studies of this effect have been conducted on van der Waals complexes formed in supersonic jet expansions in which the pDFB or pFT is bound to an argon atom. We have also explored placing the internal rotation within the complexing species instead of on the ring. A comparison of pDFB-$N_{2}$ dissociation, where $N_{2}$ is presumably nearly a free rotor, with that of pDFB-Ar provides this opportunity. The experimental evidence shows that the internal rotation of the methyl group on the ring contributes importantly to the dynamics of vibrational predissociation (VP). The VPs of pDFB-Ar and pFT-Ar, as determined from the $S_{1} - S_{0}$ fluorescence spectra, are completely different. Acceleration of the dissociation is pronounced in the pFT-Ar system. Most importantly, the high mode selectivity of the dissociation observed in pDFB-Ar and analogous aromatic complexes is largely destroyed. Further, the pFT product of the pFT-Ar dissociation is formed with the methyl rotor excited. We interpret this behavior as a consequence of rotor participation in IVR within the complex that precedes the actual dissociation. In contrast, the nearly free rotation of $N_{2}$ within the complex seems to play little role in the dissociation dynamics. pDFB-$N_{2}$ and pDFB-Ar have almost identical dissociation characteristics. In fact, one can use very similar modelling to describe VP in both of these complexes.en_US
dc.format.extent115704 bytes
dc.publisherOhio State Universityen_US

Files in this item


Items in Knowledge Bank are protected by copyright, with all rights reserved, unless otherwise indicated.

This item appears in the following Collection(s)

Show simple item record