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.