Jet Spectroscopy of the D122B1−Da12B1D_{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 $800 cm^{-1}$ $^{a}$

ELECTRONIC SPECTROSCOPY OF JET COOLED THIOPHENOXYL RADICAL

Author Institution: Faculty of Information Sciences, Hiroshima City University; Department of Chemical and Biological Sciences, Japan Women's UniversityThe thiophenoxyl radical, $C_{6}H_{5}-S (\phi-S)$, is an aromatic free radical with a benzyl type $\pi$-electronic structure. We have generated the $\phi$-S by ArF laser photolysis in supersonic free jet expansions, and observed laser induced fluorescence (LIF) of the green-blue band. We have measured the vibrationally and rotationally resolved LIF excitation spectra and the vibrationally resolved LIF dispersed spectra from single vibronic levels (SVL). On the basis of the precise vibrational analysis of the dispersed spectra, we propose new vibrational assignments to the excitation spectrum. The band types of the vibronic bands determined from the rotationally resolved excitation spectra make it possible us to give a definite assignment of the $D_{2} 1^{2}A_{2} - D_{0} 1^{2}-B_{1}, \pi^{\ast} \leftarrow \pi$, electronic transition for the green-blue band of $\phi$-S. Based on the results of the spectroscopic assignments, we will discuss the electronic and vibrational structure of $\phi$-S both on the ground $D_{0} 1^{2}B^{1}$ and the second excited $D_{2} 1^{2}A_{2}$ states