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Updated: Apr 13, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
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Dynamics and instantaneous normal modes in a liquid with density anomalies.
1Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Ave, 639798, Singapore. Dipartimento di Scienze Fisiche, CNR-SPIN, Università di Napoli Federico II, I-80126 Napoli, Italy.
Summary
Supercooled liquids with varying densities but identical diffusion constants exhibit the same dynamic behaviors. However, their potential energy landscapes differ, indicating other factors influence diffusion.
Area of Science:
- Condensed matter physics
- Soft matter physics
- Computational chemistry
Background:
- Supercooled liquids exhibit complex dynamics related to their potential energy landscape.
- Density anomalies in liquids present unique challenges for understanding their behavior.
Purpose of the Study:
- To explore the relationship between dynamical features and potential energy landscapes in a model supercooled liquid with density anomalies.
- To determine if state points with identical diffusion constants but different densities share similar dynamical properties and landscape characteristics.
Main Methods:
- Simulating a model supercooled liquid at fixed temperature across different densities.
- Analyzing mean square displacements and self-intermediate scattering functions to probe dynamics.
- Investigating instantaneous normal modes to characterize the potential energy landscape.
Main Results:
- State points with the same diffusion constant, despite differing densities, showed identical dynamical features across all length and time scales.
- Mean square displacements and self-intermediate scattering functions collapsed for these state points.
- Potential energy landscapes differed between state points with equal diffusion constants.
- A correlation was found between the fraction of instantaneous normal modes and the diffusion constant, but it was not a one-to-one relationship.
Conclusions:
- Dynamical universality exists in supercooled liquids for state points with equal diffusion constants, irrespective of density.
- The potential energy landscape is not solely determined by diffusion constant, suggesting other landscape features are critical.
- Further investigation into additional landscape properties is necessary to fully explain diffusion in these systems.
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