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.