Solvent intermolecular polarizability response in solvation

Polarizability response spectroscopy, a two-color optical Kerr effect method, has been developed and employed to study solvent intermolecular polarizability responses to photoexcited solutes. Here, we report solvent intermolecular polarizability responses in (dipolar) solvation. The time-resolved nonresonant polarizability signals are analyzed in the frequency domain where they are fit to a functional form representing diffusive reorientational, interaction-induced, and librational motions. Diffusive reorientational motion of CHCl3 was preferentially driven following photoexcitation of Coumarin 153 while interaction-induced motion was mainly driven in CH3CN solutions. The mechanism for selective solvent responses involves the relative orientation of the solvent dipole and most polarizable molecular axes and their interaction strength to the solute dipole.