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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Nonperturbative effect of attractive forces in viscous liquids
Ludovic Berthier1, Gilles Tarjus
1Laboratoire des Colloïdes, Verres et Nanomatériaux, Université Montpellier II and CNRS, 34095 Montpellier, France.
Physical Review Letters
|November 13, 2009
Summary
Attractive forces significantly impact viscous liquid dynamics, contradicting assumptions that repulsion alone governs behavior. Computer simulations reveal distinct structural and dynamic differences, even when static correlations remain similar.
Area of Science:
- Condensed matter physics
- Computational materials science
- Physical chemistry
Background:
- Glass-forming liquids exhibit complex dynamics near the glass transition.
- Intermolecular forces, particularly attractive and repulsive components, govern liquid behavior.
- Current models often assume repulsive forces dominate dense liquid dynamics.
Purpose of the Study:
- To investigate the specific role of attractive intermolecular forces in the viscous dynamics of a simple glass-forming liquid.
- To compare the structural and dynamic properties of a liquid with and without attractive interactions.
- To challenge the prevailing assumption about the dominance of repulsive forces in dense liquids.
Main Methods:
- Utilizing computer simulations to model a standard Lennard-Jones glass-forming liquid.
- Comparing two systems: one with the full Lennard-Jones potential and one with only the repulsive part.
- Analyzing static pair correlations and dynamic properties, including viscous slowing down.
Main Results:
- Significant quantitative and qualitative differences in viscous slowing down were observed between the two systems over a wide density range.
- Static pair correlations showed minimal changes, remaining largely similar for both potentials.
- The dynamics of the viscous liquid regime were found to be strongly influenced by attractive forces.
Conclusions:
- The attractive tail of intermolecular potentials plays a crucial role in the viscous dynamics of glass-forming liquids.
- The common assumption that repulsive forces solely determine the behavior of dense nonassociated liquids is invalid for relaxation dynamics.
- Understanding attractive forces is essential for accurately modeling and predicting the behavior of glass-forming liquids.
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