Surface diffusion coefficients by thermodynamic integration: Cu on Cu(100)

TL;DR

This paper calculates the diffusion rate of copper adatoms on Cu(100) surfaces using thermodynamic integration, confirming the method's accuracy and the validity of the Arrhenius law across various temperatures.

Contribution

It demonstrates the equivalence of thermodynamic integration within transition state theory and molecular dynamics for diffusion rate calculations.

Findings

Thermodynamic integration yields diffusion coefficients matching molecular dynamics results.

Activation energy and entropy are temperature-independent, supporting Arrhenius law validity.

The study confirms the effectiveness of thermodynamic integration for surface diffusion analysis.

Abstract

The rate of diffusion of a Cu adatom on the Cu(100) surface is calculated using thermodynamic integration within the transition state theory. The results are found to be in excellent agreement with the essentially exact values from molecular-dynamics simulations. The activation energy and related entropy are shown to be effectively independent of temperature, thus establishing the validity of the Arrhenius law over a wide range of temperatures. Our study demonstrates the equivalence of diffusion rates calculated using thermodynamic integration within the transition state theory and direct molecular-dynamics simulations.