Dispersion coefficients for the interactions of the alkali and alkaline-earth ions and inert gas atoms with a graphene layer

TL;DR

This paper calculates van der Waals dispersion coefficients for various ions and inert gases interacting with a graphene layer using a relativistic many-body approach within the Dirac model, providing functional fits for practical use.

Contribution

It introduces precise calculations of dispersion coefficients for multiple atomic systems with graphene, incorporating dynamic polarizabilities and temperature effects, with fitted functional forms for ease of application.

Findings

Dispersion coefficients are accurately computed for ions and inert gases with graphene.

Functional forms of the coefficients are provided for different separation distances.

Temperature effects are incorporated into the dispersion coefficient calculations.

Abstract

Largely motivated by a number of applications, the van der Waals dispersion coefficients ($C_3$s) of the alkali ions (Li$^+$, Na$^+$, K$^+$ and Rb$^+$), the alkaline-earth ions (Ca$^+$, Sr$^+$, Ba$^+$ and Ra$^+$) and the inert gas atoms (He, Ne, Ar and Kr) with a graphene layer are determined precisely within the framework of Dirac model. For these calculations, we have evaluated the dynamic polarizabilities of the above atomic systems very accurately by evaluating the transition matrix elements employing relativistic many-body methods and using the experimental values of the excitation energies. The dispersion coefficients are, finally, given as functions of the separation distance of an atomic system from the graphene layer and the ambiance temperature during the interactions. For easy extraction of these coefficients, we give a logistic fit to the functional forms of the dispersion coefficients in terms of the separation distances at the room temperature.