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Updated: Jun 14, 2025
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
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Molecular-Scale Liquid Density Fluctuations and Cavity Thermodynamics.
Attila Tortorella1,2, Giuseppe Graziano3
1Scuola Superiore Meridionale, Via Mezzocannone, 4, 80138 Naples, Italy.
Entropy (Basel, Switzerland)
|August 29, 2024
Summary
Molecular density fluctuations create liquid cavities, with probabilities following a Gaussian distribution for small volumes. Cavity creation work is entropic, leading to enthalpy-entropy compensation.
Area of Science:
- Physical Chemistry
- Statistical Mechanics
- Computational Chemistry
Background:
- Molecular-level density fluctuations in liquids naturally form cavities.
- Understanding the statistics of molecules within these cavities is crucial for solvation studies.
Purpose of the Study:
- To analyze the statistics of molecular occupancy in liquid cavities.
- To investigate the relationship between reversible work, cavity creation, and molecular probabilities.
Main Methods:
- Information theory approach to predict probability distributions.
- Computer simulations across various liquid models.
- Derivation of thermodynamic changes (enthalpy, entropy) from cavity creation probabilities.
Main Results:
- Probability of molecular occupancy follows a Gaussian distribution for small observation volumes.
- Direct correlation observed between reversible work for cavity creation and the probability of finding no molecules.
- Reversible work of cavity creation is primarily entropic, stemming from solvent-excluded volume effects.
Conclusions:
- Cavity creation in liquids is an entropic process due to excluded volume effects.
- Enthalpy and entropy changes perfectly compensate during cavity creation and solvent reorganization.
- Findings align with established statistical mechanical studies on liquid systems.
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