Electron hybridization effects and the crystal structure of plutonium. Progress report as of January 31, 1984

We have largely completed the technical development (including complex computer programming) necessary to carry out bulk LMTO electron energy band calculations. Such calculations will be used to include realistic band effects in our theory of crystallographic modifications of plutonium systems brought about through hybridization (mixing) between band electrons and relatively localized 5f electrons. In addition, we have developed and applied technique for including intermediate (between L-S and j-j) intraionic coupling on the plutonium ions. Treating such intermediate coupling is necessary for a fully quantitative treatment of the electron correlation effects on the ions. We have included such intermediate coupling and the possibility of long period structures to understand the magnetic behavior of PuSb. This demonstration of the importance of these two aspects of the behavior in hybridization mediated actinide systems is significant, because our hypothesis is that the low temperature crystallographic allotropes of plutonium (i.e., α, β, γ) are the crystal structure analogues of the long period magnetic structures found in cerium and light actinide monopnictides