The nature of the Raman damping constant and its effect upon resonant light scattering from molecular systems in the weak field limit

With the use of a time dependent tetradic operator scattering formalism, a comparison is made between resonant light scattering (RLS) generated by monochromatic and pulsed excitations. This comparison reveals that the Raman damping constant is the reciprocal of the total dephasing time associated with time dependent ensembles. A discussion is given of the effect of the lifetime of both the excited resonant intermediate state (T 1 ) and the phase relationship between pairs of contributing states (T ∗ 2 ) upon the coherent and incoherent makeup of the RLS. The question of resonance Raman versus resonant fluorescence is again reexamined.