Solvent randomness and intramolecular considerations of optical responses in four-wave mixing

We determined the optical profiles of a molecular system coupled with a thermal bath in presence of intramolecular coupling. Solvent effects were explicitly considered as a random variable by modelling the non-radiative interaction with the solute. Optical susceptibilities of stochastic origin were solved through cumulant expansions in Gaussian distributions considering a white noise as a correlation function. We examined the behaviour of these properties for the solvent noise parameter and intramolecular coupling parameters. Our results show that the intensity of the nonlinear optical properties decreases with the insertion of either of the two effects considered. Finally, other considerations related to the determination of relaxation times from the symmetry properties of the optical responses in frequency space are presented.