Issue 19, 2020

Tumbling with a limp: local asymmetry in water's hydrogen bond network and its consequences

Abstract

Ab initio molecular dynamics simulations of liquid water under equilibrium ambient conditions, together with a novel energy decomposition analysis, have recently shown that a substantial fraction of water molecules exhibit a significant asymmetry between the strengths of the two donor and/or the two acceptor interactions. We refer to this recently unraveled aspect as the “local asymmetry in the hydrogen bond network”. We discuss how this novel aspect was first revealed, and provide metrics that can be consistently employed on simulated water trajectories to quantify this local heterogeneity in the hydrogen bond network and its dynamics. We then discuss the static aspects of the asymmetry, pertaining to the frozen geometry of liquid water at any given instant of time and the distribution of hydrogen bond strengths therein, and also its dynamic characteristics pertaining to how fast this asymmetry decays and the kinds of molecular motions responsible for this decay. Following this we discuss the spectroscopic manifestations of this asymmetry, from ultrafast X-ray absorption spectra to infrared spectroscopy and down to the much slower terahertz regime. Finally, we discuss the implications of these findings in a broad context and their relation to the current notions about the structure and dynamics of liquid water.

Graphical abstract: Tumbling with a limp: local asymmetry in water's hydrogen bond network and its consequences

Article information

Article type
Perspective
Submitted
25 12 2019
Accepted
04 2 2020
First published
07 4 2020
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2020,22, 10397-10411

Tumbling with a limp: local asymmetry in water's hydrogen bond network and its consequences

H. Elgabarty and T. D. Kühne, Phys. Chem. Chem. Phys., 2020, 22, 10397 DOI: 10.1039/C9CP06960G

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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