Parallel aspects of quantum molecular dynamics simulations of liquids Original Research Article

A very straightforward parallel scheme to perform Born–Oppenheimer quantum molecular dynamics simulations of liquids is presented. It is analogous to Linear Scaling methods, used in electronic structure calculations. The instantaneous liquid configurations of molecules moving in the simulation cell with periodic boundaries and minimum image convention are divided into smaller spherical clusters around each molecule. Forces, acting on the nuclei of the molecule in the middle of each cluster, are calculated independently at any suitable level of quantum mechanical sophistication. From low-end semi-empirical schemes to high-end methods containing electron correlation corrections. In this communication selected results from simulations of liquid water simulated at 300 K and normal density using ab initio Hartree–Fock level with three different basis sets are presented. Good results are obtained for the near-structure and other characteristic liquid properties of water. A simple way to implement the method by combining a conventional classical MD simulation code with any quantum chemistry package capable of performing force calculations is presented. Suggestions of suitable parallel schemes based on standard message passing techniques are given. Performance, scaling and load balancing properties are discussed and possible future directions are suggested.