A molecular dynamics study of the thermal conductivity of CaF2and UO2

Abstract

Previous experimental work has revealed an anomalous increase of thermal conductivity lambda in solid UO₂ above about 2000 K, which has been attributed to the effect of electronic excitations. The present molecular dynamics simulations of UO₂ and the closely related material CaF₂ are designed to test this explanation by providing quantitative results for the temperature dependence of lambda in the absence of electronic excitations. The simulation results for lambda , obtained by the Green-Kubo technique, are in fair agreement with the (limited) experimental results for CaF₂. For UO₂, close agreement with experiment exists for T2 at high temperatures.