Molecular Auger rates using a statistical model and ab initio wavefunctions

Total Auger rates have been calculated using the statistical model for the isoelectronic series of molecules: CH₄, NH₃, H₂O and HF based upon bound-state Hartree-Fock ab initio wavefunctions. Minimal, double zeta, and triple zeta basis sets were used. A projection operator of Beebe and Lunnell (1972) is introduced to convert the double zeta and triple zeta basis sets into an atomic orbital basis set. Application of the statistical model to determine the total Auger rates, based upon atomic orbital electron populations, is then possible with a higher quality basis set. Both core-hole and equivalent-core wavefunctions are used in the determination of the Auger rates. These results are compared to the statistical and explicit rates calculated using INDO equivalent-core wavefunctions. While the INDO approach provides a satisfactory first estimate when the statistical method is used, whenever possible ab initio core-hole studies are to be preferred.