M. Said et al., CORE-LEVEL SHIFTS AT BCC TRANSITION-METAL SURFACES DEDUCED FROM THE CALCULATION OF SURFACE SEGREGATION ENERGIES, Surface science, 287, 1993, pp. 780-784
Within the equivalent core approximation, the core level shift between
surface and bulk atoms is equal to the surface segregation energy of
an impurity of atomic number Z + 1 in a matrix of atomic number Z. The
se energies have never been calculated systematically but have been de
duced from thermodynamical data using additional approximations. We pr
esent here a tight-binding study of these segregation energies and com
pare them with previous approaches to the calculation of surface core
level shifts. The agreement between theory and experiments is signific
antly improved.