Lima, J.A.; Freire, P.T.C.; Melo, F.E.A.; Mendes Filho, J.; De Sousa, G.P.; Lima, R.J.C.; Façanha Filho, P.F.; Bordallo, H.N.: Low-temperature Raman spectra of racemate DL-Alanine crystals. Journal of Raman Spectroscopy 41 (2010), p. 808-813
10.1002/jrs.2507
Abstract:
Raman spectra of DL-Alanine crystals were investigated in the 50 – 3200 cm−1 spectral region for temperatures ranging from 15 to 295 K. The crystalline structure of DL-Alanine represents a rare example of an amino acid racemate crystallizing in a non-centrosymmetric space group. From this study, we have observed changes in the wavenumber of modes associated with both rocking of CO2− and skeletal vibrations. On the other hand, neither changes in the modes associated to CH or CH3 vibrations nor substantial modifications of the lattice modes of the crystal were observed. Such result indicates slight changes of the CO2 group orientation without observation of a solid – solid phase transition in the DL-Alanine crystal.