A-band structural dynamics of thioanisole by resonance Raman spectroscopy

The structural dynamics of thioanisole in the S 2 (ππ*) electronic state that has large oscillator strength was studied by using the resonance Raman spectroscopy. The vibrational assignments were done for thioanisole on the basis of the FT-Raman and FT-IR measurements, the density-functional theory computations and the normal mode analysis. The A- and B-band resonance Raman spectra were obtained in cyclohexane, methanol and acetonitrile, in which ten modes in A’ irreducible representations were observed. The structural dynamics were obtained according to the resonance Raman intensity pattern. The vibroinc-coupling between the S 3 (πσ*) electronic state that has no oscillator strength and the S 2 (ππ*) electronic state were revealed. We discuss the correlation between our present structural dynamics and the previous S 2 (ππ*)/S 3 (πσ*) conical intersectional dynamics revealed by resonant-enhanced two-photon ionization and the photofragment excitation spectroscopic study. Copyright © 2012 John Wiley & Sons, Ltd.