Single particle reorientation and pair correlations of methyl iodide solutions studied by depolarized Rayleigh and Raman scattering

Abstract

Concentration and temperature dependent depolarized Rayleigh light scattering spectra were obtained for an important molecular liquid—methyl iodide—using interferometry. The concentration dependent studies yielded reliable single particle rotational‐relaxation times. These single particle times were used to test the approximations used to obtain rotational‐relaxation times for CH₃I from Raman spectra. Having verified the validity of these assumptions for CH₃I, depolarized Rayleigh and Raman results were combined to study the concentration and viscosity dependences of pair correlations. Single particle relaxation times obtained from temperature and viscosity dependent studies were used to test various hydrodynamic models of molecular reorientation. The optically isotropic solvent used in the solution work consists of 46% isopentane and 54% CCl₄ (by volume).