INITIAL STATE EFFECT OF CORE-LEVEL NORMAL PHOTOELECTRON DIFFRACTION

The photoelectron modulation functions of system C(2x2)S-Ni(001),1s ( E ) and 2p(E), which correspond to 1s and 2p initial states respectively, have been calculated., It is shown that 1s (E) and 2p(E) are out of phase. This initial state effect of core-level normal photoelectron diffraction (NPD) has been proved in multiple-scattering scheme and confirmed by a comparison between theoretical and experi-mental results.