Equivalent cores method of computing core electron binding energies

Abstract

The equivalent cores method of computing core electron ionization potentials and chemical shifts is examined quantitatively, and the results from this method are compared with those from the thermochemical, ΔSCF and Koopmans' theorem methods. As basis set size is increased, differences in the chemical shifts from these methods tend to decrease. The most satisfactory agreement with experimental shifts is given by the thermochemical method using a minimal basis.