Angular Correlation of Positron-Annihilation Radiation from Cerium Hydride

Abstract

The angular correlation of positron-annihilation radiation from cerium hydride was measured for hydrogen concentrations in the range H/Ce = 1.8–2.8. The angular correlations were found to be broader than that from cerium metal and to increase in width with increasing hydrogen concentration in a manner consistent with the screened protonic model of the electronic structure. The anionic model does not provide a satisfactory explanation of the measured angular correlations.