Adsorption of para-Hydrogen on Krypton pre-plated graphite

TL;DR

This study uses Monte Carlo simulations to analyze how para-hydrogen adsorbs on krypton-preplated graphite, revealing two stable solid monolayer phases and no stable liquid phase at zero temperature.

Contribution

It provides the first theoretical characterization of para-hydrogen monolayers on krypton pre-plated graphite, identifying stable phases and their structures.

Findings

Two stable monolayer solid phases identified

No stable liquid phase observed at zero temperature

Quantum exchanges of hydrogen molecules are suppressed

Abstract

Adsorption of para-Hydrogen on the surface of graphite pre-plated with a single layer of atomic krypton is studied thoretically by means of Path Integral Ground State Monte Carlo simulations. We compute energetics and density profiles of para-hydrogen, and determine the structure of the adsorbed film for various coverages. Results show that there are two thermodynamically stable monolayer phases of para-hydrogen, both solid. One is commensurate with the krypton layer, the other is incommensurate. No evidence is seen of a thermodynamically stable liquid phase, at zero temperature. These results are qualitatively similar to what is seen for for para-hydrogen on bare graphite. Quantum exchanges of hydrogen molecules are suppressed in this system.