First-principles calculation of the KLL Auger transition energy in 3d transition metals

A first-principles, fully relativistic, many electron method was applied to the calculation of the multiplet energies in the KLL Auger transition of 3d transition metals from chromium to copper (<F>Z=24</F>–29). The method is a configuration interaction (CI) method, combined with a fully relativistic molecular orbital (MO) theory using four-component MOs. Coulomb and spin–orbit interactions are fully considered in the active CI space with no adjustable parameters. All integrals in matrix elements are numerically calculated. The models of a free atom and a metal cluster having 13–19 atoms were used. The calculated multiplet splittings showed a systematic increase as the atomic number increased over the range from the KL23L23, KL1L23, to the KL1L1 configurations. The trend originated from the increase in orbital contraction. The results obtained using metal clusters had smaller multiplet splittings between the <F>3P</F>2(KL3L3) and <F>1S</F>0(KL2L2) terms than in the case of free-atom models by about 0.2 eV. Two final-state configurations were compared to see the effect of CI in the KL23L23 multiplets. The calculated energies were well comparable to the experimentally obtained peak positions. The <F>1S</F>0 terms largely shifted by the inclusion of the CI with the KL1L1 configuration. [Copyright &y& Elsevier]