A study of shake-up satellites in Co 2p photoelectron spectra of trans-[Co(NH3)4Cl2]Cl and cis-[Co(NH3)4Cl2]Cl isomers

Mg Kα X-ray photoelectron (ESCA) spectra of the Co 2p levels have been obtained in trans- and cis-Co(NH₃)₄Cl₂]Cl isomers. It is observed that these compounds slowly decompose under X-ray irradiation. A procedure is employed to record real spectra for both the trans and cis isomers without any significant complication by the decomposition products. Three satellites are observed in both spectra at binding energies ≈ 4.8 eV, ≈ 9.3 eV, and ≈ 16.5 eV greater than that of the Co 2p_{$\text{3}\text{2}$} peak. These isomers are distinguished from one another by the sizable difference in the relative intensity of the first satellite to the main peak. The first two satellites are assigned to ligand to Co 3d shake-up transitions by use of symmetry arguments based on molecular orbital theory, while the origin of the third satellite is less certain. The implication of the results is discussed.