Vibronic Emission Spectrum of p-Xylyl Radical.

We have obtained high-resolution Fourier transform emission spectra of the à left and right arrow &Xtilde; transition of the jet-cooled p-xylyl radical in the 450-nm spectral region. The band contours of several vibronic bands are examined. By using the rotational constants obtained from previous high-resolution LIF spectra and information about the torsional constants from dispersed fluorescence experiments, both a-type and b-type band contours are simulated. Based on symmetry arguments and the results of the simulation, we have reassigned the 6a and 6b vibrational mode frequencies of the ground electronic state of the p-xylyl radical. Copyright 1999 Academic Press.