Effects of Lateral Diffusion on the Dynamics of Desorption

TL;DR

This study investigates how lateral diffusion influences desorption dynamics in a lattice-gas model, revealing that diffusion accelerates desorption while also causing coarsening of adsorbate structures, with the initial layer structure determining the dominant effect.

Contribution

It introduces a kinetic Monte Carlo simulation approach to analyze the competing effects of lateral diffusion during desorption in a simple lattice-gas model.

Findings

Diffusion accelerates desorption.

Diffusion causes coarsening of adsorbate structures.

Initial layer structure influences the dominant effect.

Abstract

The adsorbate dynamics during simultaneous action of desorption and lateral adsorbate diffusion is studied in a simple lattice-gas model by kinetic Monte Carlo simulations. It is found that the action of the coverage-conserving diffusion process during the course of the desorption has two distinct, competing effects: a general acceleration of the desorption process, and a coarsening of the adsorbate configuration through Ostwald ripening. The balance between these two effects is governed by the structure of the adsorbate layer at the beginning of the desorption process.