Mechanical approach to chemical transport

Area of Science:

• Physical Chemistry
• Chemical Thermodynamics
• Non-equilibrium Systems

Background:

• Nonequilibrium thermodynamics often lacks known transport coefficients and clear links to equilibrium relations.
• Existing models struggle to systematically derive both transport and equilibrium equations.

Purpose of the Study:

• To present a simple, intuitive model for nonequilibrium thermodynamics.
• To systematically derive transport and equilibrium equations from a single framework.
• To connect phenomenological transport coefficients with equilibrium thermodynamics.

Main Methods:

• Developed a model based on Lagrangian dynamics for dissipative chemical systems, termed physicochemical mechanics.
• Utilized one core equation to derive various thermodynamic relations.
• Applied the model to systems with small heat generation/absorption.

Main Results:

• Physicochemical mechanics systematically derives all transport and equilibrium equations.
• The model reduces to standard thermodynamics and the Gibbs-Duhem relation at equilibrium.
• Out of equilibrium, it provides relationships between transport coefficients and describes evolution under multiple external fields.
• An extension of Onsager-Casimir reciprocal relations is achieved.

Conclusions:

• Physicochemical mechanics offers a unified and intuitive approach to nonequilibrium thermodynamics.
• The model successfully bridges the gap between transport phenomena and equilibrium relations.
• It provides a powerful tool for analyzing complex systems with simultaneous transport processes.