X-RAY PHOTOELECTRON-SPECTRA OF LN 4F ELECTRONS AND THE DEGREE OF THEIR DELOCALIZATION IN TRIFLUORIDES

A relationship is established between the parameters of the spectra of Ln 4f electrons and the oxidation state of the lanthanides in their f luorides, which enables identification of the formal valence of lantha nides in their compounds. The experimental relative intensities of lin es in the spectra of Ln 4f electrons of lanthanide trifluorides LnF(3) are determined and compared with the analogous values for Ln(2)O(3) a nd the values obtained with the use of the calculated photoemission cr oss sections. It is pointed out that spectral charcteristics of Ln 4f electrons of lanthanide fluorides and oxides have much in common, and the data obtained do not contradict the previously assumed, on the bas is of calculated results, participation of the Ln 4f atomic orbitals i n molecular orbital formation in lanthanide compounds.