With the assumption of a fully screened final state and within the ($Z+1\mathrm{}$) approximation a simple semiempirical model is presented for calculating surface-core-level shifts. Numerical results are given for shifts for first, second, and third surface-layer atoms of low-index surfaces of W and Ta.

• Received 3 August 1981

DOI:https://doi.org/10.1103/PhysRevB.24.7393