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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Semiclassical approach to model quantum fluids using the statistical associating fluid theory for systems with
Víctor M Trejos1, Alejandro Gil-Villegas
1División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Guanajuato, México.
The Journal of Chemical Physics
|May 16, 2012
Summary
This study introduces an extended statistical associating fluid theory (SAFT-VRQ) incorporating quantum corrections for fluid thermodynamic properties. The new model accurately predicts properties for quantum fluids like hydrogen and helium, highlighting the importance of quantum effects beyond low temperatures.
Area of Science:
- Thermodynamics
- Quantum Mechanics
- Statistical Mechanics
Background:
- Thermodynamic properties of quantum fluids require advanced theoretical models.
- Existing models may not fully capture quantum mechanical effects across all temperature regimes.
Purpose of the Study:
- To extend the statistical associating fluid theory for potentials of variable range (SAFT-VR) to include quantum corrections.
- To develop a theoretical framework (SAFT-VRQ) applicable to both continuous and discontinuous inter-particle potentials.
- To accurately model the thermodynamic properties of quantum fluids such as hydrogen, deuterium, neon, and helium-4.
Main Methods:
- Incorporation of quantum corrections to Helmholtz free energy using the Wentzel-Kramers-Brillouin approximation.
- Derivation of Wigner-Kirkwood theory from de Broglie-Bohm formalism for continuous potentials.
- Combination of SAFT-VR with perturbation theory for discontinuous potentials, including an analytical expression for a square-well potential.
- Application of the SAFT-VRQ theory to model thermodynamic properties.
Main Results:
- The SAFT-VRQ model accurately predicts vapor-liquid equilibrium, densities, heat capacities, and Joule-Thomson coefficients for hydrogen, deuterium, neon, and helium-4.
- Quantum corrections were found to be significant for the overall behavior of fluid properties, not just at low temperatures.
- Predictions for hydrogen showed favorable comparison with existing cubic equations of state.
Conclusions:
- The SAFT-VRQ approach provides an accurate and robust method for describing thermodynamic properties of quantum fluids.
- Quantum effects play a crucial role in the thermodynamic behavior of these fluids across a wide temperature range.
- The developed theory offers a valuable tool for understanding and predicting the behavior of quantum fluids.
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