Raman study of vibrational relaxation in dichloromethane and [2H2]dichloromethane

Abstract

The polarized and depolarized Raman spectra of the ν₁(C—H stretch) and ν₃(C—Cl stretch) vibrations in dichloromethane and the ν₁(C—D stretch), ν₂(CD₂ bend) and ν₃(C—Cl stretch) vibrations in [²H₂]dichloromethane have been studied as a function of temperature throughout the liquid range. It was found that the vibrational dephasing time of the ν₁ mode is twice as long in CD₂Cl₂ as in CH₂Cl₂ and that the relaxation time of the ν₃ mode is greater in CH₂Cl₂ than in CD₂Cl₂. Modulation times determined via the Kubo lineshape formalism are similar for both the ν₁ and ν₃ vibrations in the two molecules. Reorientational correlation times calculated from the Raman lineshapes are in good agreement with reported values.