Raman spectra and normal vibrations of dipeptides. I. Glycylglycine

Abstract

Abstract We studied the Raman spectra of the zwitterionic glycylglycine crystal (GG) and its N‐deuterated analog. A normal coordinate analysis on its α‐crystalline form was performed and the effects of intra‐and intermolecular couplings are discussed. A modified Urey‐Bradley potential was used as a model of the intramolecular force field. Factor group splittings are described by the use of intermolecular potentials consisting of nonbonded atom‐atom interactions and dipole‐dipole interactions. Effects of hydrogen bonds on the vibrational frequencies of amino and carboxylate groups are also analyzed.