Adsorption of Xe and Ar on Quasicrystalline Al-Ni-Co

TL;DR

This paper models how xenon and argon atoms adsorb onto a quasicrystalline Al-Ni-Co surface, revealing that surface corrugation significantly influences atomic interactions and adsorption behavior, with results compared to experimental data.

Contribution

It introduces a detailed potential energy model for Xe and Ar adsorption on quasicrystals, incorporating surface corrugation and adatom interactions, and compares theoretical predictions with experimental observations.

Findings

Surface corrugation enhances Xe-Xe and Ar-Ar interactions.

Theoretical low coverage adsorption results agree with LEED experimental data.

Adsorption behavior differs from flat surfaces due to quasicrystal surface structure.

Abstract

An interaction potential energy between and adsorbate (Xe and Ar) and the 10-fold Al-Ni-Co quasicrystal is computed by summing over all adsorbate-substrate interatomic interactions. The quasicrystal atoms' coordinates are obtained from LEED experiments and the Lennard-Jones parameters of Xe-Al, Xe-Ni and Xe-Co are found using semiempirical combining rules. The resulting potential energy function of position is highly corrugated. Monolayer adsorption of Xe and Ar on the quasicrystal surface is investigated in two cases: 1) in the limit of low coverage (Henry's law regime), and 2) at somewhat larger coverage, when interactions between adatoms are considered through the second virial coefficient, C_{AAS}. A comparison with adsorption on a flat surface indicates that the corrugation enhances the effect on Xe-Xe (Ar-Ar) interactions. The theoretical results for the low coverage adsorption regime are compared to experimental (LEED isobar) data.