A long-range U–Nb potential for the calculation of some chemical and physical properties of the U–Nb system

Abstract

Using a newly proposed long-range formalism, an n-body U potential that could well reproduce the lattice constants, cohesive energies, and bulk modulus of uranium in its stable orthorhombic structure is constructed. In addition, the constructed U potential is able to predict a correct sequence of the structural stability and to distinguish the energy difference between the stable and high-energy structures. Both the energies and their derivatives simulated by the constructed U potential smoothly approach zero at the cutoff radius, thus avoiding the appearance of unphysical behavior in the simulations. A similar formalism is also employed to construct an n-body U–Nb potential for the U–Nb system. The constructed U–Nb potential is then applied to the simulation of the vacancy, divacancy, and surface properties of the U–Nb system, and the calculated results are found to be in agreement with the experimentally measured values and/or with those determined by other simulation methods. Moreover, the U–Nb potential is applied to study the interfacial reaction of the U/Nb multilayer through molecular dynamics simulations, and simulation determined that an amorphization transition initiates at the interface and propagates inward in a layer-by-layer mode through mutual diffusion and alloying.