DEGENERATE FOUR-WAVE MIXING AND TWO-COLOR LASER INDUCED GRATING SPECTRA OF S-1-S-0 ELECTRONIC TRANSITIONS OF BENZENE AND MONOSUBSTITUTED BENZENES IN THE GAS PHASE

摘要

S-1-S-0 electronic spectra of gaseous benzene and monosubstituted benzenes have been measured by degenerate four-wave mixing (DFWM) spectroscopy and two-color laser induced grating (TC-LIG) spectroscopy. Dependence of the DFWM intensity on laser power (I), molecular density (M) and the absorption cross section (sigma) was examined. The intensity was expressed by a formula I(3)M(2) sigma(R)(n = 3). For benzene, the DFWM spectrum in the channel three region was observed and the relative band intensity was compared with those of the absorption spectrum and laser induced fluorescence (LIF) spectrum. TC-LIG spectra were observed for benzene, toluene and chlorobenzenes. Drastic simplification was obtained for the TC-LIG spectra even at room temperature, demonstrating a remarkable reduction of spectral congestion of large polyatomic molecules. [References: 21]