Spectroscopic evidence of distinct local structures in aqueous water

Water is the most abundant liquid on Earth, yet it rarely exists in a purely pristine state and is typically found in the presence of dissolved ions.

While pure water exhibits well-known thermodynamic anomalies, these are commonly interpreted through the two-state model, in which a locally favored tetrahedral structure (LFTS) coexists with a disordered normal-liquid structure (DNLS) in dynamic equilibrium.

However, direct experimental quantification of these structural populations remains challenging, particularly in ionic environments.

In this project, we will employ molecular dynamics simulations combined with statistical mechanics to investigate the anomalous behavior of water across a range of thermodynamic conditions within the two-state framework.

Extending this approach to aqueous electrolyte solutions, we aim to examine how the spectroscopic response of water evolves systematically with ionic concentration.

In particular, we will explore the possibility of additional local structural motifs arising from ion-induced dipole ordering of surrounding water molecules.

This work seeks to develop a generalized framework for describing water structure in ionic environments and to establish a spectroscopic route for quantifying local structural populations.

The study aims to provide a molecular-level understanding of how dissolved ions influence the thermodynamic anomalies of water, with potential relevance to a wide range of aqueous systems.

Main supervisor:
Professor Xiaodong Liang