JET SPECTROSCOPY OF THE D(1)2(2)B(1)-D(0)1(2)B(1) TRANSITION OF THE P-CYANOBENZYL RADICAL

We have generated the p-cyanobenzyl radical in supersonic free expansi on, and measured the vibrationally and rotationally resolved laser ind uced fluorescence (LIF) excitation spectra and the LIF dispersed spect ra from the single vibronic levels (SVL) in the green-blue region. The lowest energy band at 20 738 cm(-1) with the strongest intensity in t he excitation spectrum has been assigned to the 0(0)(0) band of the vi sible spectrum, on the basis of the vibronic structures in the SVL dis persed spectra. Based on the band type of the 0(0)(0) band, a-type, de termined from the rotationally resolved LIF excitation spectrum, we ha ve definitely assigned the visible band to the D-1 2(2)B(1)-D-0 1(2)B( 1) electronic transition. We have found, on the grounds of the vibrati onal analysis of the dispersed spectra, that the vibronic structure of the 2(2)B(1)-1(2)B(1) electronic transition of the benzyl type is cha racterized by totally symmetric fundamental modes, 1, 8a, and 9a. (C) 1996 Academic Press, Inc.