Hydrogen adsorption on graphene and coronene: A van der Waals density functional study

Abstract

This thesis investigates hydrogen adsorption on graphene and coronene within the framework of density functional theory. The new nonlocal van der Waals density functional (vdW-DF) method is used: the original version, vdW-DF1, and the new higher accuracy version, vdW-DF2. Hydrogen adsorption is studied in the context of formation of molecular hydrogen in interstellar space, a process thought to depend on hydrogen adsorbing on a graphitic surface. Calculations were done for hydrogen above coronene and graphene with both vdW-DF1 and vdW-DF2 to investigate how these functionals perform in the case of hydrogen adsorption on a graphitic surface. All calculations were performed with the software GPAW in a non-self consistent way based on underlying selfconsistent GGA (revPBE) calculations.The calculations performed in this thesis indicate that it is important to use a spin-polarised description of the physics to get accurate results for hydrogen adsorption on a graphitic surface.