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Alternative first-principles calculation of entropy for liquids
Edmund R Meyer1, Christopher Ticknor1, Joel D Kress1
1Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Physical Review. E
|May 14, 2016
Summary
This study introduces a new method to interpret the velocity autocorrelation function (VACF) for fluid entropy extraction. The approach decomposes the VACF into gas and solid components, showing validity across diverse liquid systems.
Area of Science:
- Thermodynamics and Statistical Mechanics
- Computational Physics
- Materials Science
Background:
- The velocity autocorrelation function (VACF) is crucial for understanding fluid dynamics and thermodynamic properties.
- Existing methods for entropy extraction from VACF have been established, but alternative approaches can offer new insights.
- Accurate calculation of thermodynamic properties like entropy is vital for predicting material behavior under various conditions.
Purpose of the Study:
- To present an alternative method for interpreting the VACF of fluids.
- To apply this method for extracting entropy, drawing parallels with established techniques.
- To validate the proposed method on diverse liquid systems.
Main Methods:
- Decomposing the liquid VACF into distinct gas and solid components.
- Calculating the entropic contribution from each VACF component.
- Fitting both gas and solid portions of the VACF in the time domain.
Main Results:
- The alternative VACF interpretation method was successfully applied to a single-component liquid (liquid Al).
- The method was also validated on two-component systems, including a high-temperature H2O phase transition and a metastable liquid MgO state.
- Results were compared with existing literature data, demonstrating the validity of the proposed approach.
Conclusions:
- The developed method provides a valid alternative for interpreting VACF and extracting fluid entropy.
- The approach is versatile, applicable to single-component liquids and complex two-component systems.
- This work contributes to a more comprehensive understanding of thermodynamic properties in condensed matter.
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