Raman spectrum of crystalline α-glycine

Abstract

Raman spectrum of a single crystal of α-glycine has been photographed using α2536.5 excitation. 35 Raman lines have been recorded with frequency shifts 53, 74, 90,109, 164, 183, 199, 358, 499, 588, 677, 697,896, 925, 1038,1112, 1140, 1320, 1330, 1395, 1414, 1441, 1459, 1506, 1563, 1640, 1668, 2530, 2630,2750, 2830, 2895, 2974, 3008 and 3145. Of these 17 have been recorded' for the first time. The 6 intense lattice lines 53, 74, 109, 164, 183 and 199. have been attributed to the rotational oscillations of the 4 molecules of glycine contained in the unit cell of the crystal. Assignments have also been made for all the prominent internal frequencies. The present study confirms the existence of -+NH₃ groups and the ionisation of the carboxyl group even in the crystal.