Theoretical atomic volumes of the light actinides

The zero-pressure zero-temperature equilibrium volumes and bulk moduli are calculated for the light actinides Th through Pu using two independent all- electron, full-potential, electronic-structure methods: the full-potential linear augmented-plane-wave method and the linear combinations of Gaussinn- type orbitals-fitting function method. The results produced by these two di stinctly different electronic-structure techniques are in good agreement wi th each other, but differ significantly from previously published calculati ons using the full-potential linear muffin-tin-orbital (FP-LMTO) method. Th e theoretically calculated equilibrium volumes are in some cases nearly 10% larger than the previous FP-LMTO calculations, bringing them much closer t o the experimentally observed volumes. We also discuss the anomalous upturn in equilibrium volume seen experimentally for alpha-Pu.