A phenomenon of partial localization of core holes has been discovered. Gre
en's function calculations on a linear NiN2 cluster used as a model of the
weak chemisorption N2/Ni(100)c(2 x 2) system show that the N1s core holes i
n the ionized states of the cluster are not fully localized on the inequiva
lent nitrogen atoms as has been previously believed. The core holes in some
of the states are considerably delocalized. This leads to distinct interfe
rence effects in angularly resolved X-ray photoelectron spectra.