The relativistic equation of state of actinide metals and compounds

Abstract

The effect of spin-orbit coupling upon the calculated pressure-volume relationship is summarized. It is shown that the main effect is to increase the lattice constant, especially in Pu systems. The both measured and calculated pronounced minimum in the lattice constants of the Anlr₂ laves phase compounds at Nplr₂ is also discussed. One influence of spin-orbit coupling upon the magnetic equation of state is shown to be suppression of magnetism. Again the effects are particularly large in Pu systems. The foregoing is illustrated by a relativistic Stoner theory which explains well the absence of magnetism in Np metal and in several Pu compounds.