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Experimental Investigation of Triplet Correlation Approximations for Fluid Water
Gayani N Pallewela1, Elizabeth A Ploetz1, Paul E Smith1
1Department of Chemistry, 213 CBC Building, 1212 Mid Campus Dr. North, Kansas State University, Manhattan, KS 66506.
Fluid Phase Equilibria
|June 20, 2018
Summary
The Kirkwood Superposition Approximation (KSA) for triplet correlations in water performs poorly. Simpler power law relationships show promise for predicting fluid thermodynamics, especially at lower compressibilities.
Area of Science:
- Physical Chemistry
- Fluid Dynamics
- Statistical Mechanics
Background:
- Triplet correlations are crucial for understanding fluid properties.
- The relationship between pair and triplet correlations is of significant interest.
- Accurate models are needed to describe these correlations.
Purpose of the Study:
- To evaluate the accuracy of the Kirkwood Superposition Approximation (KSA) for triplet correlations in water.
- To investigate alternative approximate relationships between pair and triplet correlations.
- To assess the performance of these approximations across various thermodynamic states.
Main Methods:
- Utilized Fluctuation Solution Theory.
- Incorporated experimental pair radial distribution functions.
- Analyzed integrals of pair and triplet correlation functions at multiple state points for pure water.
Main Results:
- The Kirkwood Superposition Approximation (KSA) demonstrated poor performance, consistent with prior research.
- Several alternative approximate relationships were investigated.
- Good agreement for fluid thermodynamics was observed in regions of low compressibility.
Conclusions:
- The KSA is not a reliable approximation for triplet correlations in water.
- A simple power law relationship between pair and triplet fluctuations is effective, particularly for states with low to moderate compressibility.
- These findings offer improved methods for modeling fluid thermodynamics.
Keywords:
Fluctuation Solution TheoryKirkwood Superposition ApproximationTriplet Correlationsfluid thermodynamicsradial distribution functionMore Related Videos
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