Resonance hyper-Raman and Raman scattering from benzene and fluorobenzene

Abstract

The first resonance ( 1L a state) hyper-Raman spectra of benzene and fluorobenzene are reported. The benzene spectrum implies weak two-photon vibronic coupling between the 1L a and ground electronic states and is the first reported example of hyper-Raman C term scattering. The fluorobenzene spectrum is comprised of one-photon vibronically active fundamental modes, indicating strong two-photon dipole allowed electronic character. A corresponding resonance Raman spectrum confirms the primarily vibronic (one-photon) nature of the 1L a transition, although some dipole allowed activity is also evident. The results illustrate advantages of resonance hyper-Raman scattering over two-photon absorption techniques.