Charge transfer-transitions and X-ray photoelectron spectroscopy of copper(II) complexes

Satellite structure in the X-ray photoelectron (Cu 2p) spectra of some squareplanar cupric complexes has been compared to electron paramagnetic resonance and electronic spectra results on the electronic structure of these complexes. It is shown that these satellites can be assigned to various ligand → metal 3d or ligand → ligand* transitions within the monopole selection rules of the sudden approximation.