Benchmarking of classical force fields by ab initio calculations of atomic clusters: Ti and Ni–Ti case

We propose a method for benchmarking classical force fields, which is based on the ab initio calculations of small atomic clusters. As a case study, we investigate the force fields which describe interactions between Ni and Ti atoms. By studying the stability of pure and Ni-doped titanium clusters within the classical and ab initio frameworks, we evaluate the accuracy of the existing classical interatomic potentials for the description of systems on the atomistic scale, where quantum effects play a crucial role. In order to check the ability of the force fields to reproduce correctly macroscopic parameters of transition-metal systems, we perform molecular dynamics simulations of nanoindentation of the crystalline Ni–Ti alloy. As a result of the analysis performed, we demonstrate that the existing classical force fields for Ti–Ti and Ni–Ti interactions describe adequately not only the macroscopic properties of the crystalline structure, but also point defects and local irregularities which may occur in a crystal.