Mixed Valence of Ce and Its Consequences on the Magnetic State of Ce(9)Ru(4)Ga(5): Electronic Structure Studies

We report on X-ray photoelectron spectroscopy (XPS) and ab initio electronic structure investigations of a novel intermetallic material Ce [Formula: see text] Ru [Formula: see text] Ga [Formula: see text]. The compound crystallizes with a tetragonal unit cell (space group I4 [Formula: see text]) that contains three inequivalent Ce atoms sites. The Ce [Formula: see text] core level XPS spectra indicated an intermediate valence (IV) of selected Ce ions, in line with the previously reported thermodynamic and spectroscopic data. The ab initio calculations revealed that Ce1 ions located at [Formula: see text] Wyckoff positions possess stable trivalent configuration, whereas Ce2 ions that occupy [Formula: see text] site are intermediate valent. Moreover, for Ce3 ions, located at different [Formula: see text] position, a fractional valence was found. The results are discussed in terms of on-site and intersite hybridization effects.