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

Abstract
The X-ray photoemission spectra of Pr, PrH2.1 and PrH3 have been measured. The core levels of PrH3 show satellites due to H 1s to Pr 4f transitions, which become weaker in PrH2.1. PrH2.1 exhibits satellites due to Pr 5d to Pr 4f transitions and those due to the empty localised 5d level. Taking these satellite structures into account, chemical shifts between PrH2.1 and PrH3 are ambiguous while there are large implying that a charge transfer occurs from Pr to tetrahedral hydrogen but not to octahedral hydrogen. A chemical shifts between Pr and PrH2.1, hydrogen-induced band appears at about 6 eV below the Fermi energy, and comparison with theoretical densities of state suggests the importance of hybridisation between Pr 6sp and H 1s in the metal-hydrogen bonding.