Ab initio molecular dynamics simulation of liquid water with fragment-based quantum mechanical approach under periodic boundary conditions^†

In this study, we investigated the structural and dynamical properties of liquid water by using ab initio molecular dynamics simulation under periodic boundary conditions based on the fragment-based quantum mechanical approach. This study was carried out using the second-order Møller-Plesset perturbation theory (MP2) with the aug-cc-pVDZ basis set, which has been validated to be sufficiently accurate for describing water interactions. Diverse properties of liquid water, including radial distribution functions, diffusion coefficient, dipole moment, triplet oxygen-oxygen-oxygen angles, and hydrogen-bond structures, were simulated. This ab initio description leads to these properties in good agreement with experimental observations. This computational approach is general and transferable, providing a comprehensive framework for ab initio predictions of properties of condensed-phase matters.