Water and ice structure in the range 220 - 365K from radiation total scattering experiments

TL;DR

This study combines new x-ray and neutron scattering data with Monte Carlo simulations to analyze water and ice structures across 220-365K, revealing unexpected properties in both states.

Contribution

It introduces a new empirical potential refined with recent scattering data and provides a comprehensive analysis of water and ice structures over a broad temperature range.

Findings

Identification of non-intuitive water properties in liquid and solid states.

First-time presentation of new scattering data for water at 280-365K.

Analysis of older neutron data on ice 1h at 220K.

Abstract

The past decade or so has witnessed a large number of articles about water structure. The most incisive experiments involve radiation with a wavelength compatible with the observed inter-molecular separations found in water, of order $\sim 3$\AA, in other words mostly $<$1eV neutrons and $>$10keV x-rays. Because x-rays are scattered by electrons while neutrons are scattered by nuclei, the two probes give complementary information about the three site-site radial distribution functions for water, namely O-O, O-H and H-H. Here a version of Monte Carlo simulation called Empirical Potential Structure Refinement is used to devise an empirical intermolecular potential which attempts to drive the simulated radial distribution functions as close as possible to the data. New x-ray and neutron scattering data on water in the temperature range 280 - 365K are presented for the first time, alongside a new analysis of some much older neutron data on ice 1h at 220K. This temperature analysis, above and below the water freezing point of water, reveals some non-intuitive water properties in the liquid and solid states.