Electron density of states of interstitial impurities in transition metals: H in Pd

Abstract

The theory developed by Riedinger (1971) to calculate the Green function and electron density of states for a metal-impurity system in terms of a model Hamiltonian description of the pure metal bandstructure is extended to the case of interstitial impurities in transition metals. The theory is applied to dilute concentrations of hydrogen in palladium. The perturbing potential is assumed to be a screened Coulomb potential together with an exchange and correlation contribution and the screening parameter is determined from the Friedel sum rule. Calculations of the perturbed electronic density of states are performed for the hydrogen occupying tetrahedral and octahedral sites in the palladium crystal structure. While there is strong perturbation of the palladium valence band, no bound states are formed below the bottom of the band. Such states have resulted from some previous calculations on palladium hydride systems.