Anisotropic He-C Pair Interaction for a He Atom Near a Graphite Surface

Abstract

Recent scattering data are employed to study the interaction $V\left(\overrightarrow{\mathrm{r}}\right)$ between a He atom and a graphite surface. Assuming $V\left(\overrightarrow{\mathrm{r}}\right)$ can be written as a sum of He-C interactions $U(\overrightarrow{\mathrm{r}}-{\overrightarrow{\mathrm{R}}}_i)$, it is found that none of a variety of central potentials $U\left(\right|\mathrm{}\overrightarrow{\mathrm{r}}-{\overrightarrow{\mathrm{R}}}_i\mathrm{}\left|\right)\mathrm{}$ considered is consistent with the data. In contrast, an anisotropic pair potential agrees with scattering and thermodynamic data, and with estimates derived from the electronic properties of graphite.