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

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.