Esca study of some chromium complexes: ionization energies and multi-peak structure of the spectra

The chemical shifts of the core ionization energies of C₆H₆CrC₆H₆, C₆H₆Cr(CO)₃, COOCH₃C₆H₅Cr(CO)₃ and Cr(CO)₆ have been measured and information on the bonding of these complexes has been obtained. In the spectra of the complexes studied the main peaks have been frequently found to be accompanied by smaller ones, whose intensities and energies are structure dependent. In an attempt to assign these “extra” peaks, the energy separations from the main peak have been compared with the ultraviolet absorption energies of the neutral molecules.