We numerically investigate the structure of deep supercooled and glassy water under pressure, covering the range of densities corresponding to the experimentally produced high- and very-high-density amorphous phases. At $T=188\mathrm{K}$, a continuous increase in density is observed on varying pressure from 2.5 to 13 kbar, with no signs of first-order transitions. Exploiting a recently proposed approach to the analysis of the radial distribution function—based on topological properties of the hydrogen-bond network—we are able to identify well-defined local geometries that involve pairs of molecules separated by multiple hydrogen bonds, specific to the high- and very-high-density structures.

• Received 7 July 2021
• Accepted 9 September 2021

DOI:https://doi.org/10.1103/PhysRevLett.127.175502