DENSITY-FUNCTIONAL CALCULATION OF CORE-ELECTRON BINDING-ENERGIES OF GLYCINE CONFORMERS

Our recent procedure of computing accurate core-electron binding energ ies (CEBEs) with density-functional theory is applied to glycine confo rmers in this work. The procedure uses the unrestricted generalized tr ansition-state model and a combined functional of Becke's 1988 exchang e with Perdew's 1986 correlation. When a large basis set such as Dunni ng's correlation-consistent polarized valence quadruple zeta set is us ed, the average absolute deviation from experiment for the CEBEs of th e most stable conformer of glycine is only 0.2 eV, compared with 18 eV for Koopmans' theorem.