Raman band intensities of some local group modes of α‐Glycine, L ‐alanine and DL ‐alanine crystals

Band intensities in the polarized Raman spectra have been measured for the CO2− stretching, the CH2 stretching and the CH2 bending modes of α‐glycine crystal and the CO2− stretching and the CH3 symmetric deformation modes of L‐ and DL‐alanine crystals. Variations in the relative band intensities on the change of the scattering geometry have been elucidated by applying the oriented gas model to the local groups, –CH2, –CH3 and –CO2−, of these amino acid crystals. The calculated values of the components of the derived polarizability tensors are consistent with the geometry of the groups. The depolarization ratios estimated from the calculated anisotropy of the polarizability tensors have been compared with those observed for aqueous solutions.