Ab InitioMolecular Dynamics for Simple Liquid Metals Based on the Hypernetted-Chain Approximation

Abstract

Abstract We present an ab initio molecular dynamics (MD) method for simple liquid metals based on the quantal hypernetted-chain (QHNC) theory derived from exact expressions for radial distribution functions (RDF's) of the electron-ion model for liquid metals. In our method based on the QHNC equations, the classical MD is performed repeatedly to determine a self-consistent effective interionic potential, which depends on the ion-ion RDF of the system. This resultant effective ionic potential is obtained to be consistent with the density distribution of a pseudoatom and the electron-ion RDF, as well as the ion-ion RDF and the ion-ion bridge function, which are determined exactly as a result of the repeated MD simulation. We have applied this QHNC-MD method for Li, Na, K, Rb, and Cs near the melting temperature using upto 16,000 particles for the MD simulation. It is found that the convergence of the effective interionic potential is fast enough for practical applications; typically two MD runs are enough fo...