Testing interatomic potentials for binary alloys using exact solutions to the equations of atomic motion

Abstract

The molecular dynamics (MD) method provides important information about the behavior of defects in metals and alloys, their mechanical properties, possible phase transitions, etc. The application of the MD method requires the use of accurate interatomic potentials. Many potentials have now been developed for pure metals and alloys, and there is a need for rigorous testing of their accuracy. In this work, a set of exact oscillatory solutions to the nonlinear equations of motion of atoms in the B2 structure based on the bcc lattice is described and offered to solve this problem for a number of binary alloys with this structure. The solutions are called delocalized nonlinear vibrational modes (DNVMs); they have a small spatial period and their frequency response can be easily obtained with the use of ab initio simulations and then used for testing the interatomic potentials.