Molecular-dynamics simulation of liquid water with an<i>ab initio</i>flexible water-water interaction potential

TLDR

The authors extended the MCY configuration‑interaction potential to include intramolecular vibrations and performed ab initio molecular‑dynamics simulations of liquid water, computing static and dynamic properties without empirical parameters and comparing them to experiment. Most properties improved slightly relative to the MCY model, and the simulated high‑frequency sound mode supports recent coherent inelastic neutron scattering results.

Abstract

The Matsuoka-Clementi-Yoshimine (MCY) configuration interaction potential for rigid water-water interactions has been extended to include the intramolecular vibrations. The extended potential (MCYL), using no empirical parameters other than the atomic masses, electron charge, and Planck constant, is used in a molecular-dynamics simulation study of the static and dynamic properties of liquid water. Among the properties studied are internal energy, heat capacity, pressure, radial distribution functions, dielectric constant, static structure factor, velocity autocorrelation functions, self-diffusion coefficients, dipole autocorrelation function, and density and current fluctuations. Comparison with experiments is made whenever possible. Most of these properties are found to improve slightly relative to the MCY model. The simulated high-frequency sound mode seems to support the results and interpretation of a recent coherent inelastic neutron scattering experiment.