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Updated: Jun 28, 2026
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Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
Facilitation, complexity growth, mode coupling, and activated dynamics in supercooled liquids
Sarika Maitra Bhattacharyya1, Biman Bagchi, Peter G Wolynes
1Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India.
Summary
In supercooled liquids, activated hopping facilitates continuous diffusion, revealing a cooperative dynamic. This theory explains relaxation behavior and predicts key parameters like stretching exponent beta and relaxation timescale tau.
Area of Science:
- Condensed matter physics
- Physical chemistry
- Soft matter physics
Background:
- Supercooled liquids exhibit complex dynamics below the ideal mode-coupling theory transition temperature.
- Hopping and continuous diffusion processes coexist in these systems.
- Understanding the interplay between these dynamics is crucial for explaining liquid behavior.
Purpose of the Study:
- To develop a theory explaining the coexistence and interplay of hopping and continuous diffusion in supercooled liquids.
- To investigate how activated hopping facilitates continuous diffusion.
- To validate the theory using experimental data from Salol.
Main Methods:
- Development of a theory combining mode-coupling theory (MCT) and random first-order transition (RFOT) theory.
- Analysis of nonlinear interactions between continuous diffusion and activated hopping.
- Application of the theory to the specific system of Salol.
Main Results:
- The theory explicitly shows activated hopping facilitating continuous diffusion.
- Nonlinear coupling between dynamics leads to universal features and modifies relaxation behavior.
- The theory accurately predicts the temperature dependence of the stretching parameter (beta) and alpha relaxation timescale (tau) for Salol.
- The theory explains the applicability of MCT below the ergodic-to-nonergodic transition.
- Predicted variations of beta with fragility parameter D align with experimental observations.
Conclusions:
- Activated hopping plays a crucial role in facilitating continuous diffusion in supercooled liquids.
- The developed theory provides a unified framework for understanding complex dynamics in these systems.
- The theory's success in predicting Salol's properties validates its approach and highlights a 'facilitation effect' in structural relaxation.
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