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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Calculating thermodynamic properties from fluctuations at small scales
Sondre K Schnell1, Xin Liu, Jean-Marc Simon
1Process and Energy Laboratory, Delft University of Technology, Leeghwaterstraat 44, 2628CA Delft, The Netherlands.
The Journal of Physical Chemistry. B
|August 16, 2011
Summary
Density and energy fluctuations in small systems can determine macroscopic thermodynamic properties. This method, using finite size scaling, extrapolates properties from small to large systems, applicable to various fluids and heterogeneous systems.
Area of Science:
- Thermodynamics
- Statistical Mechanics
- Computational Chemistry
Background:
- Macroscopic thermodynamic properties are crucial for understanding material behavior.
- Determining these properties often requires large-scale simulations or experiments.
- Finite size effects in small systems pose challenges for accurate property prediction.
Purpose of the Study:
- To develop a method for determining macroscopic thermodynamic properties from small, nonperiodic systems.
- To apply this method to calculate enthalpy density, thermodynamic correction factors, and Kirkwood-Buff integrals.
- To validate the finite size scaling approach for extrapolating properties to the macroscopic limit.
Main Methods:
- Utilizing density and energy fluctuations of small systems embedded in a reservoir.
- Applying finite size scaling analysis, dependent on system length (1/L).
- Extrapolating properties from small systems to the macroscopic limit using surface effect scaling.
Main Results:
- Demonstrated a convenient method for obtaining total correlation function integrals (Kirkwood-Buff integrals) for mixtures.
- Successfully applied the method to Weeks-Chandler-Andersen (WCA) and Lennard-Jones (LJ) fluids.
- Validated the approach for a heterogeneous system: argon adsorbed in silicalite-1 zeolite.
Conclusions:
- The proposed method effectively determines macroscopic thermodynamic properties from small systems.
- Finite size scaling provides a reliable way to extrapolate properties, especially when systems are far from critical points.
- This approach offers a computationally efficient alternative for calculating key thermodynamic parameters.
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