Core-level shifts of low coordination atoms at the W(320) stepped surface

We study the surface core-level shifts (SCLS's) at the W(320) surface by ab initio calculations, including both initial-state and final-state effects. This stepped surface features (110) terraces with five atom rows, separated by single atomic steps. We find that the final-state effect is important for the proper prediction of the SCLS at the W(320) surface. Unlike the W(110) surface where the final-state effect increases the SCLS to lower binding energy, the reverse is true in the W(320) surface, indicating inefficient core-hole screening at the stepped surface. Our results provide a theoretical basis for the interpretation of core-level photoemission spectra from the W(320) surface.