MD Simulation of Molten (Na-2Cs)Cl Containing UO₂²⁺ with Fixed Intraionic Charge Distribution

Abstract

We performed trial MD simulations for molten (Na-2Cs)Cl containing 10 wt% of UO₂²⁺ at 1100 K. In order to incorporate different function forms between alkali halides and UO₂, the Tosi-Fumi potentials used for the former were converted to the function form of the latter. From the viewpoints of both the bulk structure and local structure around UO₂²⁺, dependence of these structures was examined on the charge distribution in UO₂²⁺ using pair distribution functions, the coordination number, and snapshots. It was found that the bulk structure of the solvent was not influenced by the charge distribution in UO₂²⁺, although the local structure of UO₂²⁺ depended strongly on that in UO₂²⁺. Homogeneous dispersion of the UO₂²⁺ ions was observed in the case of the charge distribution in UO₂²⁺ with (Z_U, Z_O) = (4, −1), and the coordination number of CI⁻ around the U atoms was four.