X-ray photoemission study of the electronic structure of praseodymium hydride

The x-ray photoemission spectra of Pr, PrHsub(2.1) and PrH3 have been measured. The core levels of PrH3 show satellites due to H 1s → Pr 4f transitions, which become weaker in PrHsub(2.1). PrHsub(2.1) exhibits satellites due to Pr 5d → Pr 4f transitions and those due to the empty localised 5d level. Taking these satellite structures into account, chemical shifts between PrHsub(2.1) and PrH3 are ambiguous while there are large chemical shifts between Pr and PrHsub(2.1), implying that a charge transfer occurs from Pr to tetrahedral hydrogen but not to octahedral hydrogen. A hydrogen-induced band appears at about 6 eV below the Fermi energy, and comparison with theoretical densities of states suggests the importance of hybridisation between Pr 6sp and H 1s in the metal-hydrogen bonding. (author)