The structure of X-ray photoelectron spectra of light actinide compounds

The results of X-ray photoelectron spectroscopy (XPS) studies of the structures of the outer and inner electron shells of compounds of light actinides (Th, U, Np, Pu, Am, Cm, Bk, Cf) in the binding energy (E_b) range of 0–1250 eV are generalised. The regularities of formation of the fine structure in the X-ray photoelectron (XPS) spectra of these compounds are considered. The mechanisms of appearance of such structure are analysed, and the correlations between the fine structure parameters and actinide oxidation states and local environment, the magnetic properties of compounds, the nature of the chemical bond and secondary electronic processes that accompany photoemission of electrons are discussed. Experimental evidence for effective formation of the outer (E_b = 0–15 eV) and inner valence (E_b = 15–50 eV) molecular orbitals, in particular, from the fully occupied An6p and Lns orbitals of the neighbouring actinide (An) and ligand (L) atoms in the compounds in question is presented. The use of fine spectral structure parameters, together with the electron binding energies and line intensities extends significantly the scope of application of the XPS method in structural studies.