Theoretical analyses of pressure induced glass transition in water: Signatures of surprising diffusion-entropy scaling across the transition

Abstract

Because of the negative inclination of the solid–liquid phase separation line in water, ice Ih melts on compression. We carry out molecular dynamics simulations using TIP4P/Ice water model. We find that increase in pressure drives the liquid water into a high density metastable glassy state, at relatively high pressure (greater than ∼30 kbar). The crystal-to-glass transition is characterised by a rapid approach to a zero diffusion state and absence of crystalline order in the static structure factor. The vitrification is found to occur even at high temperatures (T > 250 K). We study this novel glass transition process at four temperatures (80, 250, 300 and 320 K). The transition pressure increases with an increase in temperature, as expected. Interestingly, we find that the total rate of change of entropy with pressure undergoes a change at/near the glass transition. We discover a pressure-induced realignment of water molecules resulting in two well-separated peaks in the O–O–O angle distribution among neighbouring molecules. The difference between the positions of these two peaks undergoes a sharp change at the vitrification pressure suggesting that it can serve as an appropriate order parameter to detect the glass transition point.

GRAPHICAL ABSTRACT

KEYWORDS:

• glass transition
• diffusion
• entropy
• amorphous ice
• O–O–O angle

Acknowledgement

The author conveys that is a pleasure to dedicate this article to Professor Michael Klein who has been a valuable and helpful colleague (friend, philosopher and guide) over many years (or decades). BB thanks DST, India, for partial funding of this work, and SERB, India for providing National Science Chair (NSC) Professorship. SM thanks DST, India for INSPIRE fellowship and IISc for Institute Research Associateship. All the simulations were performed in the Cray Supercomputer ‘SahasraT’ stationed at the SERC (Supercomputer Education and Research Centre) Department of IISc.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Indian Institute of Science and Science and Engineering Research Board [grant number SB/NSC/2019/02].