THE ROTATIONALLY RESOLVED ELECTRONIC SPECTRUM OF THE DIFLUOROBENZENE-$N_{2}$ VAN DER WAALS $COMPLEX^{a}$
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Date
1999
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Ohio State University
Abstract
The rotationally resolved $S_{1} \leftarrow S_{0}$ fluorescence excitation spectra of para-difluorobenzene (pDFB) and its $N_{2}$ complex have been observed. The high resolution spectrum of pDFB is pure b-type and spans an unusually wide energy region of over $20 cm^{-1}$. The $N_{2}$ complex of pDFB exhibits two absorption bands shifted to the red of the bare molecule origin, at -27 and $-25cm^{-1}$. Each of these bands is a superposition of the two pure c-type spectra that result from the internal rotation of the $N_{2}$ molecule in the complex. Analyses of these bands show that the $N_{2}$ molecule lies $^{-} 3.59$ {\AA} above the center of the ring plane in the $S_{a}$ state; this distance decreases to $^{-}3.47$ {\AA} in the $S_{1}$ state. The barriers to internal rotation in the two electronic states are also different. A full discussion of the factors responsible for the difference will be given.
Description
$^{a}$ work supported by NSF
Author Institution: Department of Chemistry, University of Pittsburgh
Author Institution: Department of Chemistry, University of Pittsburgh