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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
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From Single-Particle to Collective Dynamics in Supercooled Liquids
Dmitry V Matyushov1, Ranko Richert2
1School of Molecular Sciences and Department of Physics, Arizona State University, Post Office Box 871504, Tempe, Arizona 85287-1504, United States.
The Journal of Physical Chemistry Letters
|May 17, 2023
Summary
This study presents a model explaining differences between photon correlation spectroscopy (PCS) and dielectric spectroscopy (BDS) by linking single-particle and collective dynamics. The model successfully predicts dielectric spectra from photon correlation data for supercooled liquids.
Area of Science:
- Physical Chemistry
- Materials Science
- Spectroscopy
Background:
- Photon correlation spectroscopy (PCS) and dielectric spectroscopy (BDS) probe molecular dynamics.
- A significant difference exists between PCS and BDS spectra due to their sensitivity to single-particle versus collective dynamics, respectively.
Purpose of the Study:
- To develop a model that connects single-particle dynamics (from PCS) to collective dynamics (from BDS).
- To explain the narrower width and shifted peak position observed in BDS spectra compared to PCS spectra.
Main Methods:
- Utilizing single-particle susceptibility data derived from PCS studies.
- Developing a model with a single adjustable parameter to link PCS and BDS spectra.
- Testing the model on supercooled liquids: glycerol, propylene glycol, and tributyl phosphate.
Main Results:
- The model successfully accounts for the differences between BDS and PCS spectra.
- The single adjustable parameter correlates molecular angular velocity cross-correlations and relaxation times.
- Demonstrated good agreement for glycerol, propylene glycol, and tributyl phosphate.
Conclusions:
- The developed model provides a framework for understanding the relationship between single-particle and collective dynamics in supercooled liquids.
- This work is a step towards rationalizing material-specific dielectric loss profiles based on universal PCS spectra.
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