Photoemission and X-ray absorption studies of intermetallic compounds based on the early rare earths

The general motivation for this thesis was to better understand the 4f instability in Cerium-based systems and hybridization effects involving the 4f electrons in Pr- and Nd- as well as Ce-based systems, by applying X-ray photoelectron spectroscopy, resonant photoelectron spectroscopy and X-ray absorption spectroscopy. The result of an ancillary study, not directly relevant to the main theme of the thesis is reported which addresses the problem of chemisorption-induced surface disproportionation in ReNi5, Re=La, Pr and Nd, a subject of current interest in catalysis and hydrogen storage problem. Deep-core XPS studies on ReRu2 and Relr2 systems, Re = La, Ce, Pr and Nd, show that there can be appreciable but decreasing intensity of the shake-down satellite in the 3d-XPS spectrum in going from La to Nd. The hybridization between the 4f electrons and the conduction electrons in the presence of a deep core hole has been deduced from the relative intensity of the shakedown satellite.