Thermodynamic discontinuity between low-density amorphous ice and supercooled water

Area of Science:

• Computational physics and chemistry
• Materials science
• Thermodynamics

Background:

• Amorphous ice exists in various forms, with low-density amorphous ice (LDA) being a common state.
• Understanding the phase behavior of water, especially its amorphous and supercooled states, is crucial for various scientific fields.
• Previous studies have explored the properties of LDA, but its transformation pathways remain an active area of research.

Purpose of the Study:

• To investigate the structural and thermodynamic properties of low-density amorphous ice (LDA) using advanced simulation techniques.
• To identify potential phase transitions of LDA under varying conditions.
• To assess the impact of quantum mechanical effects on the water phase diagram.

Main Methods:

• Employed a combination of reverse Monte Carlo (RMC) simulations for structural analysis.
• Utilized molecular dynamics (MD) simulations to capture dynamic behavior and thermodynamic properties.
• Incorporated lattice dynamics (LD) simulations to account for vibrational contributions and quantum effects.

Main Results:

• Obtained detailed structural and thermodynamic data for LDA.
• Identified a thermodynamically discontinuous phase transformation occurring at approximately 130 K.
• This transformation leads to a phase consistent with the properties and structure of supercooled liquid water.

Conclusions:

• The study demonstrates a key phase transition in LDA, linking it to supercooled water.
• Quantum corrections were found to significantly alter thermodynamic properties and critical points in the water phase diagram.
• These findings provide new insights into the complex phase behavior of water and its amorphous forms.