Relaxation and decay of an atom with a core-hole. IV

The charge transfer core-hole screening depends on the ratio between the ch arge transfer rate and the rate of change in separation-energies between th e acceptor and donor levels in a charge transfer system. The latter is rela ted to how fast a photoelectron leaves the system. As examples we discussed the core-level XPS spectra of the NZ molecule physisorbed on graphite and the L-23 XPS spectra of the formally pure divalent Cu compounds such as CuO and YBa2 Cu-3 O7-delta. The interplay between the adiabatic transition and the non-adiabatic transition upon a core-electron ionization (excitation) in a charge transfer system is discussed in the light of the relaxation and core-hole decay. (C) 2001 Elsevier Science B.V. All rights reserved.