Molecular dynamics of acetophenone and its derivatives investigated by femtosecond optical Kerr effect spectroscopy and depolarized low-frequency Raman scattering

We present the results of femtosecond optical heterodyne-detected optical Kerr effect spectroscopy (OHD-OKE) on acetophenone and its derivatives: o-hydroxybenzaldehyde, o-methylacetophenone, and o-hydroxyacetophenone. The depolarized Raman scattering spectra were also measured, and compared with the frequency-domain representations of the OHD-OKE data. An oscillatory motion, corresponding to an intramolecular vibrational Raman mode, is clearly detected in the OHD-OKE transient for each of these liquids. The slow orientational relaxation times of o-hydroxybenzaldehyde and o-hydroxyacetophenone imply the existence of strong intermolecular interactions induced by hydrogen bond exchange.