Ni 2p resonant photoelectron spectra of some planar nickel complexes

Resonant photoelectron spectra in the Ni 3s, 3p and 3d regions were investigated at the Ni 2p edge for the planar nickel complexes K2Ni(CN)4 and bis-(dimethylglyoximato)nickel(II). A number of satellite series, which are observed weakly or are absent in the off-resonant spectra, are enhanced through the resonant excitation for both samples. The enhanced satellite bands lower the electron kinetic energy with increasing photoexcitation energy and converge to the normal Auger lines at the Ni 2p ionization threshold. Furthermore, the electron kinetic energy dependence on the photon energy is different between these complexes. This behavior is characteristic of one-electron exciton states in molecular solids.