SOLVENT DEPENDENCE OF VIBRATIONAL DEPHASING AND REORIENTATIONAL RELAXATION

The polarized and depolarized Roman spectra of the v1 band of chloroform and deuterochloroform were obtained as a function of concentration in the solvents carbon tetrachloride, acetonitrile, and acetone. The reorientational correlation functions were found to decay more rapidly in CCl4 but more slowly in the two polar solvents; these results contrast directly with the behavior predicted by models of rotational diffusion. The isotropic correlation functions were analyzed with the model of vibrational dephasing, as described recently by Rothschild. It was observed that the modulation (or collision) times increase in the nonpolar CCl4 and in acetone but remain constant in the second polar solvent, acetonitrile. An interpretation of the above results in terms of specific solute-solvent interactions is presented. © 1979 American Institute of Physics.