Electronic structure of heavy-element oxides and fluorides: XANES LIII spectroscopy and DFT calculations

XANES LIII spectra of series Tl, Pb and Bi compounds are studied. The data of DFT–ZORA calculations are in satisfactory agreement with the results of XANES spectroscopy of heavy-element fluorides and oxides. The fine structure of LIII absorption near edge for Tl3+, Pb4+ and Bi5+ ions is associated with transitions to the atomic 6s1/2, 6p1/2 (relativistic allowed) and 6d–7s terms. The “superfluous” lines observed in XANES spectra of Tl+, Pb2+ and Bi3+ oxides and fluorides are associated with the mix of 6s1/2 and 6p3/2 states of heavy 6s2 ions.