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Theoretical study of Sutherland fluids with long-range, short-range, and highly short-range potential parameters
Jianguo Mi1, Yiping Tang, Chongli Zhong
1Department of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
The Journal of Chemical Physics
|February 13, 2008
Summary
This study explores Sutherland fluid behavior using modified theories like FMSA, RG, and DFT. It shows which theoretical approaches best describe fluid properties across different interaction ranges and thermodynamic states.
Area of Science:
- Thermodynamics
- Statistical Mechanics
- Fluid Theory
Background:
- Sutherland fluids are model systems for studying intermolecular forces.
- Understanding fluid behavior across various thermodynamic states is crucial.
- Existing theories may have limitations in describing diverse interaction potentials.
Purpose of the Study:
- To investigate the phase behavior of Sutherland fluids using various theoretical frameworks.
- To evaluate the effectiveness of modified first-order mean spherical approximation (FMSA) theories.
- To determine the optimal theoretical approach for different interaction ranges and thermodynamic conditions.
Main Methods:
- Utilized the first-order mean spherical approximation (FMSA) theory.
- Applied modifications including the simplified exponent approximation, renormalization group (RG) transformation, and density functional theory (DFT).
- Analyzed fluid behavior for Sutherland fluids with parameters gamma=3.1-36.
Main Results:
- Original FMSA accurately describes global phase behavior, including the critical region, for long-range interactions.
- Modified FMSA with simplified exponent approximation is effective outside the critical region for short-range forces.
- RG transformation is suitable inside the critical region, and DFT combined with FMSA excels for extremely short-range forces.
Conclusions:
- The choice of theoretical approach depends on the interaction range and thermodynamic state.
- Modified FMSA, RG, and DFT offer complementary strengths for describing Sutherland fluid behavior.
- This work provides insights into the applicability of different theories for diverse physical scenarios.
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