Resonance polarization CARS of pyrene in the lowest excited singlet state

Abstract
Polarization CARS of pyrene in the S1 state has been observed in solution at room temperature under the resonance condition with the SnS1 transient absorptions. The polarization behaviors of totally symmetric ag and nontotally symmetric b1g modes have been interpreted on the basis of an irreducible tensor formulation of the polarization CARS susceptibility which is applicable rigorously in resonance conditions, and anomalous depolarization ratio for the b1g mode corresponding to the case of ρl >3/4 in spontaneous Raman scattering has been deduced.