Quantum mechanical behavior of an H atom on Cu(111) and Pt(111)

The quantum mechanical behavior of an H atom adsorbed on Cu(111) and on Pt(111) is investigated. The potential energy curves (PECs) for the H atom motion on these surfaces are calculated within the density functional theory, and the adiabatic three-dimensional potential energy surfaces (PESs) are constructed based on the obtained PECs. The wave functions and their energies for the H atom motion on the PESs are calculated within the framework of the variation method. The results show that, in the case of Cu(111), the ground state wave function is strongly localized around the fcc hollow site, the first-excited state wave function is strongly localized around the hcp hollow site, and these states almost energetically degenerate. On the other hand, the second-excited state wave function is delocalized and extends from the fcc hollow site to the bridge site and further to the hcp hollow site. Then, there is a significant energy gap between the first- excited and the second-excited state. In the case of Pt(111), the ground and the first-excited state wave functions are delocalized and extend from the hollow site to the bridge site. The second-excited state wave function further extends over the top site. The energy differences between the ground and the first-excited state, and between the first-excited and the second-excited state are very small. Thus, the H atom adsorbed on Pt(111) has a delocalized nature. (C) 2000 American Institute of Physics.