Pressure Induced Vibrational Relaxation and Electronic Dephasing in Molecular Solids

Abstract

Conventional Raman spectroscopy under high pressure conditions has been a useful probe of molecular solids. More recently, time-resolved coherent Raman experiments in high pressure diamond anvil cells have been used as a probe of pressure induced vibrational dephasing in benzene (Baggen et al 1987; Della Valle et al 1988) and nitromethane (Rice et al 1989) at room temperature. However, time-resolved measurements of pressure induced dephasing at room temperature have been complicated by thermally induced dephasing and relaxation processes. In order to minimize inhomogeneous and thermally induced dephasing we have performed high pressure picosecond CARS measurements on high pressure single crystals at low temperature (Chronister et al 1991; Baggen et al 1991) as well as photon echo measurements on doped molecular solids at high pressure.