Revealing the three-dimensional structure of liquids using four-point correlation functions

Area of Science:

• Materials Science
• Statistical Physics
• Soft Matter Physics

Background:

• Disordered systems (liquids, gels, glasses, granular materials) are vital in nature and industry.
• Their microscopic 3D structure remains poorly understood, unlike crystalline solids.
• Current methods provide limited, spherically averaged structural information.

Purpose of the Study:

• To introduce a novel, simple method for probing the 3D structure of disordered systems.
• To elucidate the complex 3D structural ordering in various liquid types.
• To identify the characteristic symmetries governing liquid structures.

Main Methods:

• Utilized computer simulations to analyze disordered systems.
• Developed and applied nonstandard correlation functions to capture 3D structural details.
• Investigated systems ranging from hard sphere liquids to open network liquids like silica.

Main Results:

• Identified distinct 3D structural orders in liquids at intermediate and large scales.
• Hard sphere liquids show alternating icosahedral and dodecahedral symmetries.
• Open network liquids, such as silica, exhibit tetrahedral symmetry.

Conclusions:

• Liquids possess a complex, non-trivial 3D structure.
• This structural information is encoded in specific nonstandard correlation functions.
• The new method provides unprecedented insight into the 3D organization of disordered matter.