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Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Thermodynamic geometry, phase transitions, and the Widom line
G Ruppeiner1, A Sahay, T Sarkar
1Division of Natural Sciences, New College of Florida, 5800 Bay Shore Road, Sarasota, Florida 34243-2109, USA. ruppeiner@ncf.edu
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|December 11, 2012
Summary
A new method using thermodynamic curvature (R) characterizes liquid-gas phase transitions. This approach accurately determines coexistence curves and the Widom line without problematic constructions.
Area of Science:
- Thermodynamics
- Phase Transitions
- Statistical Mechanics
Background:
- First-order liquid-gas phase transitions are fundamental in physical chemistry.
- The Maxwell equal area construction is conventionally used but has limitations.
- Characterizing the supercritical regime, including the Widom line, remains an active research area.
Purpose of the Study:
- To propose a novel microscopic characterization for first-order liquid-gas phase transitions.
- To develop a method for determining liquid-gas coexistence curves without the Maxwell construction.
- To enable direct determination of the Widom line in the supercritical regime.
Main Methods:
- Utilizing thermodynamic curvature (R) as a microscopic characterization parameter.
- Proposing that R is equal in coexisting phases near the critical point.
- Relating R to the correlation volume (ξ(3)) near the critical point.
Main Results:
- A new method for determining liquid-gas coexistence curves is presented, avoiding the Maxwell equal area construction.
- The relationship |R| ~ ξ(3) allows for direct determination of the Widom line in the supercritical region.
- The proposed method is illustrated using the van der Waals model and NIST Chemistry WebBook data.
Conclusions:
- Thermodynamic curvature offers a robust framework for analyzing liquid-gas phase transitions.
- The proposed method provides a more accurate and direct approach to phase transition characterization.
- This work advances the understanding of critical phenomena and supercritical fluid behavior.
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