Insights into the Second Law of Thermodynamics from Anisotropic Gas-Surface Interactions

TL;DR

This paper explores how anisotropic gas-surface interactions influence thermodynamic behavior, revealing conditions for reversibility and nonequilibrium states, and clarifying the second law's constraints on such interactions.

Contribution

It demonstrates that microscopic anisotropy can lead to macroscopic reversibility and nonequilibrium states, challenging traditional views on the second law in surface interactions.

Findings

Anisotropy can induce reversibility at the macroscopic scale.

Surface anisotropy can sustain nonequilibrium stationary states.

Second law prohibits anisotropic interactions in equilibrium.

Abstract

Thermodynamic implications of anisotropic gas-surface interactions in a closed molecular flow cavity are examined. Anisotropy at the microscopic scale, such as might be caused by reduced-dimensionality surfaces, is shown to lead to reversibility at the macroscopic scale. The possibility of a self-sustaining nonequilibrium stationary state induced by surface anisotropy is demonstrated that simultaneously satisfies flux balance, conservation of momentum, and conservation of energy. Conversely, it is also shown that the second law of thermodynamics prohibits anisotropic gas-surface interactions in "equilibrium", even for reduced dimensionality surfaces. This is particularly startling because reduced dimensionality surfaces are known to exhibit a plethora of anisotropic properties. That gas-surface interactions would be excluded from these anisotropic properties is completely counterintuitive from a causality perspective. These results provide intriguing insights into the second law of thermodynamics and its relation to gas-surface interaction physics.