VIBRATIONAL ANALYSIS OF GLYCINE ZWITTERION - AN AB-INITIO STUDY

It is known that the ab initio electronic structure calculations on is olated amino acid zwitterions do not reproduce experimental vibrationa l frequencies and their potential energy distribution(PED), obtained f rom solution and/or solid phases, because of intramolecular hydrogen b onding. In this paper we show that using Onsager reaction field model with a proper choice of basis set, cavity radius and dielectric consta nt followed by the scaling of force constants can indeed mimic the fea tures of the experimental results very well for the simplest amino aci d glycine zwitterion. (C) 1998 Elsevier Science B.V. All rights reserv ed.