Trapping of electrons near chemisorbed hydrogen on graphene

TL;DR

This study uses ab-initio DFT calculations to analyze how negatively charged graphene interacts with chemisorbed hydrogen, revealing electron trapping near the hydrogen atom and resulting in a singlet ground state.

Contribution

It provides a detailed computational analysis of electron trapping and spin state changes due to hydrogen chemisorption on charged graphene, highlighting the role of electron affinity.

Findings

Electron affinity dominates the energetic balance in charged systems.

Extra electrons are attracted near the chemisorbed hydrogen.

Chemisorption results in a singlet ground state.

Abstract

Chemical adsorption of atomic hydrogen on a negatively charged single layer graphene sheet has been analyzed with ab-initio Density Functional Theory calculations. We have simulated both finite clusters and infinite periodic systems to investigate the effect of different ingredients of the theory, e.g. exchange and correlation potentials, basis sets, etc. Hydrogen's electron affinity dominates the energetic balance in the charged systems and the extra electron is predominantly attracted to a region nearby the chemisorbed atom. The main consequences are: (i) the cancellation of the unpaired spin resulting in a singlet ground-state, and (ii) a stronger interaction between hydrogen and the graphene sheet.