We report on a study of the empty states at the Cu/Si(111)7 x 7 interf
ace via polarization-dependent Cu L(2,3) X-ray absorption spectrescopy
(XAS) as a function of the Cu coverage (0.25-5ML). Joint analysis of
the CuL(3) XAS line-shapes of Cu-based reference compounds allows us t
o interpret the high coverage spectra in terms of pseudo-stoichiometri
c Cu-silicides.