The equivalent cores approximation: An ab initio study of nuclear relaxation energies and charge distributions

Abstract

Ab initio 6-31G * Hartree-Fock SCF calculations have been performed on the C 1s ionized states of aniline and the corresponding equivalent core ions (the aminopyridinium ions) at the aniline optimized geometry. Together with results from the geometry-optimized amino-pyridinium ions, the effect of nuclear relaxation of the equivalent core ions on calculated binding energy shifts and the use of equivalent core ions for predicting electronic properties of core hole states are investigated.