Behavior of H atom in adsorption states on metal surfaces – localization and delocalization

We investigate the quantum mechanical behavior of an H atom adsorbed on metal surfaces. The potential energy curves (PECs) for the H atom adsorbed on Cu(1 1 1) and on Pt(1 1 1) are calculated within the density functional theory, and the model potential energy surfaces (PESs) are constructed based on the obtained PECs. And, the wave functions for the H atom on the PESs are calculated. We discuss the localization/delocalization of the H atom adsorbed on metal surfaces in terms of the wave functions of the H atom. In the case of Cu(1 1 1), the wave function is localized around the so-called fcc hollow site. In the case of Pt(1 1 1), the wave function extends from the fcc hollow site to the bridge site and to the so-called hcp hollow site, that is, the wave function is delocalized on the surface.