Core level shifts in the3dtransition metals and tin

Abstract

We present estimates of various contributions to the free-atom-metal binding-energy shifts, $\Delta E_B$, for the $2s$ and $2p$ core levels of the iron series elements and, for comparison, the $3d_{\frac{5}{2}}$ level of Sn. Our results indicate that the sharp break in the experimental $\Delta E_B$ values occurring between Ni and Cu is due to variation in differences of $d$-electron count, i.e., $d$ configuration, between atom and metal. Ley et al. who neglected the $d$-configuration differences, attributed the break in $\Delta E_B$ to a change in extra-atomic screening. Through free-atom calculations we find extra-atomic screening energies of 6-8 eV for Ti through Zn, with no break between Ni and Cu, and ∼ 10 eV for Sn. In conjunction with charge-renormalization and dipole-term estimates, these results suggest that intra-atomic screening of core holes in metals is an important factor influencing free-atom-metal binding-energy shifts.