So-called ‘relaxation’ mode located at 0.1 cm−1 in the low-frequency Raman spectra of ethylene glycol - acetone mixtures

Low frequency Raman spectra of ethylene glycol(EG) and acetone mixtures are investigated by high-resolution double monochrometer. A broad peak located at 0.1 cm−1 in susceptibility spectra is compared with the dielectric loss spectra. Both Raman relaxation time(τMRT1) and dielectric relaxation time(τD1) are determined by the model fitting method. The ratio τMRT1/τD1 does not depend on static dielectric constant of mixtures and is almost constant, ≈3.2, from 1.0 (pure EG) to 0.3 mole fraction. This result indicates that both τMRT1 and τD1 are determined by the same molecular dynamics.