Related Experiment Video
Updated: Jul 10, 2025
12:37
Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers
Published on: September 4, 2015
12.4K
Thermodynamic stability at phase coexistence
Jozismar Rodrigues Alves1, Vera Bohomoletz Henriques1
1Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, CEP: 05508-090, São Paulo, SP, Brasil.
Physical Review. E
|November 18, 2023
Summary
This study resolves thermodynamic instability in phase-separating systems by introducing interface thermodynamics. Correcting simulation misinterpretations restores true chemical potential convexity and enables accurate surface tension calculation.
Area of Science:
- Thermodynamics
- Statistical Mechanics
- Computational Physics
Background:
- Phase-separating systems exhibit "Van der Waals-like" isotherms in simulations.
- Unstable regions in thermodynamic fields violate the second law of thermodynamics.
- The origin of these unstable regions is often attributed to phase interfaces.
Purpose of the Study:
- To rationalize the violation of the second law of thermodynamics by entropy in simulations.
- To introduce a thermodynamic description of the interface between coexisting phases.
- To re-interpret simulation measurements of thermodynamic potentials.
Main Methods:
- Developed a new thermodynamic framework for interfaces in phase-separating systems.
- Re-interpreted existing simulation data using the new framework.
- Verified the adapted theory using simulations of the 2D lattice gas model.
Main Results:
- The corrected interpretation of thermodynamic potentials eliminates unstable regions.
- The thermodynamic description of interfaces restores the proper convexity of chemical potential isotherms.
- Direct calculation of surface tension shows excellent agreement with Onsager's prediction.
Conclusions:
- The study provides a physically sound explanation for observed thermodynamic instabilities.
- The new approach corrects misinterpretations in simulation data analysis.
- This work offers a method for accurate surface tension calculation in phase-separating systems.
More Related Videos
Related Concept Videos
01:19Phase Diagram
5.9K
The phase of a given substance depends on the pressure and temperature. Thus, plots of pressure versus temperature showing the phase in each region provide considerable insights into the thermal properties of substances. Such plots are known as phase diagrams. For instance, in the phase diagram for water (Figure 1), the solid curve boundaries between the phases indicate phase transitions (i.e., temperatures and pressures at which the phases coexist).
5.9K
02:31Phase Transitions
19.1K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
19.1K
02:39Phase Transitions: Melting and Freezing
12.4K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
12.4K
02:39Phase Diagrams
41.1K
A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. These diagrams indicate the physical states that exist under specific conditions of pressure and temperature and also provide the pressure dependence of the phase-transition temperatures (melting points, sublimation points, boiling points). Regions or areas labeled solid, liquid, and gas represent single phases, while lines or curves represent...
41.1K
01:23Stability of Equilibrium Configuration
449
Understanding the stability of equilibrium configurations is a fundamental part of mechanical engineering. In any system, there are three distinct types of equilibrium: stable, neutral, and unstable.
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
449
01:21Path Between Thermodynamics States
3.2K
Consider the two thermodynamic processes involving an ideal gas that are represented by paths AC and ABC in Figure 1:
3.2K