Static and Dynamic Correlations in Water: Comparison of Classical Ab Initio Molecular Dynamics at Elevated Temperature with Path Integral Simulations at Ambient Temperature

CH Li and F Paesani and GA Voth, JOURNAL OF CHEMICAL THEORY AND COMPUTATION, 18, 2124-2131 (2022).

DOI: 10.1021/acs.jctc.1c01223

It is a common practice inab initiomolecular dynamics (AIMD)simulations of water to use an elevated temperature to overcome the overstructuringand slow diffusion predicted by most current density functional theory (DFT)models. The simulation results obtained in this distinct thermodynamic state are thencompared with experimental data at ambient temperature based on the rationale thata higher temperature effectively recovers nuclear quantum effects (NQEs) that aremissing in the classical AIMD simulations. In this work, we systematically examinethe foundation of this assumption for several DFT models as well as for the many-body MB-pol model. Wefind for the cases studied that a higher temperature does notcorrectly mimic NQEs at room temperature, which is especially manifest in significantly different three-molecule correlations as wellas hydrogen bond dynamics. In many of these cases, the effects of NQEs are the opposite of the effects of carrying out thesimulations at an elevated temperature.

Return to Publications page