Laser jet spectra of methyl 3-chlorobenzoate

The (1 þ 1) REMPI spectrum and the fluorescence excitation spectrum of methyl 3-chlorobenzoate were measured in the supersonic free jet. In the fluorescence excitation spectrum, only one strong 0–0 band along with a few vibronic bands was observed although this compound has two stable conformers. In the REMPI spectrum, the 0–0 band of the other conformer and many vibronic bands in addition to the bands appearing in the fluorescence excitation spectrum were observed. This phenomenon can be explained by means of the conformational difference in the rate of the intersystem crossing between the S1 and a triplet states. q 2004 Elsevier B.V. All rights reserved