The vibrational and rotational relaxation of iodine in solution by resonance Raman lineshape measurement

Abstract

The isotropic linewidths of a series of overtones in the resonance Raman spectrum of a dilute solution of I₂ and CCl₄ were measured. The widths enabled the mechanism responsible for the vibrational dephasing to be identified as a vibrational frequency modulation. The transition between the fast and slow modulation regimes could be followed, by observing the dependence of overtone width on overtone order, and a characteristic time and mean square amplitude ascribed to the frequency modulation process.

The anisotropic linewidths for the I₂ anisotropic spectra in a séries of solvents, chosen for the wide range of their viscosity, were also measured. The reorientation time was found to vary linearly with solvent viscosity.