Adsorbate-adsorbate interactions and chemisorption at different coverage studied by accurate {\em ab initio} calculations: CO on transition metal surfaces

TL;DR

This study uses advanced DFT calculations to analyze how CO molecules interact and adsorb on transition metal surfaces at various coverages, revealing the key factors influencing adsorption patterns.

Contribution

It introduces a first-principles extrapolation method to accurately compute chemisorption energies for CO on transition metals at different coverages.

Findings

Adsorbate through-space repulsion influences pattern formation.

Bonding competition affects preferred adsorption sites.

Substrate-mediated electron delocalization plays a role in adsorption behavior.

Abstract

We use density functional theory (DFT) with the generalized gradient approximation (GGA) and our first-principles extrapolation method for accurate chemisorption energies {[Mason {\em et al.}, Phys. Rev. B {\bf 69}, 161401R (2004)]} to calculate the chemisorption energy for CO on a variety of transition metal surfaces for various adsorbate densities and patterns. We identify adsorbate through-space repulsion, bonding competition, and substrate-mediated electron delocalization as key factors determining preferred chemisorption patterns for different metal surfaces and adsorbate coverages. We discuss how the balance of these interactions, along with the inherent adsorption site preference on each metal surface, can explain observed CO adsorbate patterns at different coverages.