1ST-PRINCIPLES CALCULATIONS OF THE SPECIFIC-HEAT MASS ENHANCEMENTS INUIR3, UPT3, AND UAU3

By including dynamic fluctuations around the local-density-approximati on (LDA) electronic structure we find good agreement for the specific- heat mass-enhancement factors for UX3 (X = lr, Pt, Au). The fluctuatio ns, which are calculated through to second order in the perturbation, are restricted to those caused by strong, local, uranium 5f electron-e lectron interactions, for which the calculated effective interaction s trength is 2 eV. The strong material dependence of the second-order ma ss-enhancement factors is related to the composition dependence of the Fermi energy and the underlying one-electron LDA density of states.