Assessing Order in Liquid, Supercooled, and Crystalline Water

Area of Science:

• Physical chemistry
• Condensed matter physics
• Materials science

Background:

• Water exhibits complex hydrogen bonding (H-bonding) networks in aqueous solutions.
• Understanding water's structural organization is crucial across various thermodynamic states.

Purpose of the Study:

• To introduce a generalized approach for analyzing the H-bond network connectivity in water.
• To develop a novel metric, the ring summation factor, for quantifying water's structural order.

Main Methods:

• Developed a method to identify and classify H-bond rings based on donor-acceptor directionality.
• Constructed a ring summation factor metric, analogous to the tetrahedral order parameter.
• Applied the metric to liquid, supercooled, and crystalline water systems.

Main Results:

• The ring summation factor effectively characterizes water ordering across different phases.
• Network ordering in liquid water is state-dependent and sensitive to simulation models.
• Supercooled water exhibits a universal ring distribution signature preceding crystallization.
• Different ice polymorphs show distinct ring size distributions and proton ordering.

Conclusions:

• The ring summation factor provides a new perspective on water structure and ordering.
• This metric can identify and help correct deficiencies in tetrahedrality assessments of crystalline water.
• The findings offer insights into water's behavior in liquid, supercooled, and solid states.