# Mass Density Fluctuations in Quantum and Classical descriptions of Liquid Water

## TL;DR

This paper establishes a first-principles molecular dynamics protocol using revPBE-D3 to study water, comparing structural and density fluctuation properties across different models and ensembles, enhancing understanding of water's microscopic behavior.

## Contribution

It introduces a consistent simulation protocol for water using revPBE-D3 and compares structural and density fluctuation properties across multiple models and ensembles.

## Key findings

- revPBE-D3 accurately describes water properties at ambient conditions
- Structural properties are consistent across NpT and NVT ensembles
- Density fluctuations vary with different interaction potentials

## Abstract

First principles molecular dynamics simulation protocol is established using revised functional of Perdew-Burke-Ernzerhof (revPBE) in conjunction with Grimme's third generation of dispersion (D3) correction to describe properties of water at ambient conditions. This study also demonstrates the consistency of the structure of water across both isobaric (NpT) and isothermal (NVT) ensembles. Going beyond the standard structural benchmarks for liquid water, we compute properties that are connected to both local structure and mass density uctuations that are related to concepts of solvation and hydrophobicity. We directly compare our revPBE results to the Becke-Lee-Yang-Parr (BLYP) plus Grimme dispersion corrections (D2) and both the empirical fixed charged model (SPC/E) and many body interaction potential model (MB-pol) to further our understanding of how the computed properties herein depend on the form of the interaction potential.