On electrons and hydrogen-bond connectivity in liquid water

TL;DR

This paper investigates the hydrogen-bond network in liquid water using electronic signatures from ab initio simulations, revealing dynamic reshaping of electronic structures but persistent bonding between water molecules.

Contribution

It introduces a novel approach to analyze water's hydrogen bonds based on electronic signatures rather than geometric criteria, supported by ab initio molecular dynamics.

Findings

Electronic network shows continuous reshaping with oscillations.

Hydrogen bonds persist over multiple oscillation periods.

Electronic signatures provide a dynamic view of hydrogen bonding.

Abstract

The network connectivity in liquid water is revised in terms of electronic signatures of hydrogen bonds (HBs) instead of geometric criteria, in view of recent X-ray absorption studies. The analysis is based on ab initio molecular-dynamics simulations at ambient conditions. Even if instantaneous thread-like structures are observed in the electronic network, they continuously reshape in oscillations reminiscent of the r and t modes in ice (tau~170 fs). However, two water molecules initially joint by a HB remain effectively bound over many periods regardless of its electronic signature.