Electronic structure and optical properties of ThPd3 and UPd3

We present calculations of the electronic and optical properties of the act inide compounds ThPd3 and UPd3 using the state-of-the-art full-potential li nearized augmented-plane-wave method as implemented in the WIEN97 code. Bot h compounds crystallize in the complex TiNi3 structure with 16 atoms per un it cell. For comparison with earlier work, we also studied these compounds in the AuCu3 structure. However, we find that the results in this hypotheti cal structure do not compare that well with experiments as in the actual Ti Ni3 structure. We have calculated the density of states (DOS), the coeffici ent of the electronic specific heat, and the frequency dependent optical co nductivity. These quantities are compared with experiments where good agree ment is obtained. The DOS is dominated by Pd d stares below the Fermi energ y and by actinide f states near and above the Fermi energy. Transitions bet ween these states dominate the optical conductivity and we find that the op tical matrix elements do not play an important role. This finding is suppor ted by experiments on a comparison of x-ray photoemission spectroscopy (XPS ) data with optical conductivity.