Laser-induced fluorescence spectra of jet cooled p-chlorobenzyl radical

We have generated the p-chlorobenzyl radical in supersonic free expansion, and measured the laser-induced fluorescence (LIF) excitation spectra and LIF dispersed spectra from single vibronic levels (SVL). Based on an analysis of the dispersed spectra, we find the two band origins, spaced only 94 cm−1 apart, of the D1 1 2A2− and D2 2 2B1−D0 1 2B1 transitions in the excitation spectrum. We also observe interstate level mixing between the 6b and 12 vibronic levels of the D2 and D1 states, respectively, in the excitation spectrum, and the vibronic coupling is analyzed using a simple model within the Born-Oppenheimer (B-O) approximation.