Casimir-Polder force and torque for anisotropic molecules close to conducting planes and their effects on CO$_2$

TL;DR

This paper derives the Casimir-Polder force and torque for anisotropic molecules near conducting surfaces, applying the results to CO2 and graphene, and suggests potential for improving CO2 separation technologies.

Contribution

It provides new tensorial expressions for Casimir-Polder interactions involving anisotropic molecules near conducting planes, including specific applications to CO2 and graphene.

Findings

CO2 molecules tend to align perpendicular to conducting surfaces

Casimir torque can influence molecular orientation near surfaces

Potential application in enhancing CO2 separation membranes

Abstract

We derive the Casimir-Polder force and Casimir torque expressions for an anisotropic molecule close to a conducting plane with a tensorial conductivity. We apply our general expressions to the case of a carbon dioxide CO$_2$ molecule close to a plane with pure Hall conductivity and to graphene. We show that the equilibrium position of this linear molecule is with its main axis perpendicular to the surface. We hence conjecture a possible way to exploit the Casimir torque to mechanically improve the performance of CO$_2$ separation membranes useful for an efficient atmospheric CO$_2$ reduction.