Density Functional Theory study of contribution of many-body energies to binding energy for alanine-(water)4 complex

The lowest energy conformer of alanine-(water), complex (Spectrochim. Acta A, 59, 2619, 2003) was studied in more detail using Density Functional Theory methods B3LYP/6-31+G*. The total energy and binding energy for this complex is -629.514437 hartrees and -41.02 kcal/mol, respectively. Relaxation energy and many-body energies, i.e., two-, three-, four-, and five-body energies, were obtained for this complex using many-body analysis to elucidate their contribution to the binding energy of the complex. It was found that relaxation energy as well as all many-body energies had significant contributions to the total binding energy. The highest contribution is from two-body energies. (C) 2004 Wiley Periodicals, hic.