Can xenon in water inhibit ice growth? Molecular dynamics of phase transitions in water$-$Xe system

Abstract

Motivated by recent experiments showing the promise of noble gases as cryoprotectants, we perform molecular dynamics modeling of phase transitions in water with xenon under cooling. We study the structure and dynamics of xenon water solution as a function of temperature. Homogeneous nucleation of clathrate hydrate phase is observed and characterized. As the temperature is further reduced we observe hints of dissociation of clathrate due to stronger hydrophobic hydration, pointing towards a possible instability of clathrate at cryogenic temperatures and conversion to an amorphous phase comprised of "xenon + hydration shell" Xe$\cdot$(H${}_2$O)${}_{21.5}$ clusters. Simulations of ice$-$xenon solution interface in equilibrium and during ice growth reveal the effects of xenon on the ice$-$liquid interface, where adsorbed xenon causes roughening of ice surface but does not preferentially form clathrate. These results provide evidence against the ice-blocker mechanism of xenon cryoprotection.

Supplementary videos at http://dx.doi.org/10.1063/1.4887069 and https://www.youtube.com/playlist?list=PLfw-sxJ8wx2sZr94QGCvuo4vwEDBBaXES

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• Canonical sampling through velocity-rescaling
• How the Liquid-Liquid Transition Affects Hydrophobic Hydration in Deeply Supercooled Water
• Heat Capacity Effects Associated with the Hydrophobic Hydration and Interaction of Simple Solutes: A Detailed Structural and Energetical Analysis Based on MD Simulations

Cited by in corpus (1)

• Simulations of supercooled water under passive or active stimuli