Pressure-induced transformations in glassy water: A computer simulation study using the TIP4P/2005 model.

Area of Science:

• Physical Chemistry
• Materials Science
• Computational Physics

Background:

• Amorphous solid water exists in multiple forms, including low-density amorphous (LDA) and high-density amorphous (HDA) ice.
• Understanding the transitions between these forms under pressure is crucial for various scientific fields.

Purpose of the Study:

• To investigate pressure-induced transformations between LDA and HDA ice using molecular dynamics (MD) simulations.
• To evaluate the performance of the TIP4P/2005 water model in reproducing experimental observations of these transformations.

Main Methods:

• Out-of-equilibrium molecular dynamics (MD) simulations were performed using the TIP4P/2005 water model.
• Simulations covered compression and decompression cycles to study LDA-HDA and HDA-LDA transformations.
• Radial distribution functions and densities were analyzed to characterize the ice structures.

Main Results:

• The TIP4P/2005 model qualitatively reproduced LDA-HDA transformations, including structural and density changes.
• A P-T phase diagram for glassy water was constructed, showing consistency with experimental data.
• The model's diffusion coefficient D(T) at 0.1 MPa followed mode coupling theory predictions.

Conclusions:

• The TIP4P/2005 model is a reliable tool for simulating amorphous ice transformations.
• The study provides insights into the phase behavior of glassy water and supports the possibility of a liquid-liquid phase transition.
• MD simulation results were robust against variations in simulation rates and aging.