Hydrogen-bond potential for ice VIII-X phase transition

Area of Science:

• Physical Chemistry
• Materials Science
• Condensed Matter Physics

Background:

• Hydrogen bonds (O-H:O) in water and ice exhibit unique recoverability and sensitivity.
• The repulsive force between bonding electrons and nonbonding pairs is often overlooked.

Purpose of the Study:

• To develop a potential model for the hidden repulsive force opposing ice compression.
• To elucidate the mechanism of the ice VIII-X phase transition.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Analysis of neutron scattering observations.
• Development of a potential model incorporating covalent, dispersion, and hidden forces.

Main Results:

• Charge polarization leads to asymmetric relaxation of H-O and O:H bonds before the VIII-X transition.
• Proton centralization towards phase X observed due to opposite potential curvatures.
• The potential model accurately reproduces the experimentally observed VIII-X phase transition.

Conclusions:

• The hidden repulsive force plays a critical role in ice phase transitions.
• The developed potential model offers insights into water anomalies.
• Understanding these forces is key to predicting water and ice behavior.