Stokes and anti-stokes hyper-Raman scattering from benzene, deuterated benzene, and carbon tetrachloride

Hyper-Raman spectra from liquid benzene, deuterated benzene, and carbon tetrachloride are observed using a cw pumped Q-switched mode-locked Nd:YAG laser and a synchronously gated two-dimensional single-photon-counting detector. Both Stokes and anti-Stokes peaks are observed and assigned to hyper-Raman active vibrational modes, some of which are forbidden in the Raman and infrared spectra of benzene and deuterated benzene. The effect of the stimulated Raman process in populating the vibrational levels and modifying the hyper-Raman spectra is discussed.