Jet Spectroscopy of the $D_{1} 2^{2}B_{1} - D_{a} 1^{2}B_{1}$ Electronic Transition of the p-Cyanobenzyl Radical

$^{a}$M. Fukushima, K. Obi, Chem. Phys. Lett. 248, 269 (1996)Author Institution: Advanced Technology Research Center, Mitsubishi Heavy Industries, LTD.; Department of Chemistry, Tokyo Institute of TechnologyWe have generated the $p$-cyanobenzyl radical in supersonic free expansion, and measured the laser induced fluorescence (LIF) spectra in gree-blue region; the vibrationally and rotationally resolved LIF excitation spectra and the LIF dispersed spectra from the single vibronic levels ( SVL ) On the basis of the vibronic structures in the SVL dispersed spectra, the lowest energy band at $20735 cm^{-1}$ with the strongest intensity in the excitation spectrum has been assigned to the $0^{0}_{0}$ band of the visible spectrum. Based on the band type of the $0^{0}_{0}$ band, a-type, determined from the rotationally resolved LIF excitation spectrum, we have 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 vibrational 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 was charactersized by totally symmetric fundamental modes, 1, 8a, and 9a, with the frequencies higher than $800 cm^{-1}$, while those of the $1^{2}A_{2} - 1^{2}B_{1}$ electronic transition are non-totally symmetric modes, 6b and 8b, and totally symmetric modes, 6a and 1, with the frequencies lower than $800 cm^{-1}$ $^{a}$