Anisotropic contribution to the van der Waals and the Casimir-Polder energies for CO$_2$ and CH$_4$ molecules near surfaces and thin films

TL;DR

This paper investigates how the anisotropic polarizability of CO$_2$ and the isotropic polarizability of CH$_4$ affect their van der Waals and Casimir-Polder energies near surfaces, explaining their different surface interactions.

Contribution

It provides a quantitative analysis of the influence of molecular polarizability anisotropy on dispersion energies near surfaces, a novel focus in surface-molecule interaction studies.

Findings

Anisotropic polarizability significantly alters the van der Waals energy for CO$_2$.

Isotropic polarizability results in different energy contributions for CH$_4$.

The study clarifies the role of molecular polarizability in surface interaction differences.

Abstract

In order to understand why carbon dioxide (CO$_2$) and methane (CH$_4$) molecules interact differently with surfaces, we investigate the Casimir-Polder energy of a linearly polarizable CO$_2$ molecule and an isotropically polarizable CH$_4$ molecule in front of an atomically thin gold film and an amorphous silica slab. We quantitatively analyze how the anisotropy in the polarizability of the molecule influences the van der Waals contribution to the binding energy of the molecule.