Atomic resonances of hydrogen near aluminum surfaces: Adiabatic evolution of the ground state

Complex adiabatic potential curves are an essential input to atomic surface scattering calculations employing the coupled-states method. We present calculations for the ground state of hydrogen near a jellium surface with the density of aluminum. Two complementary techniques have been implemented: the complex rotation method and the stabilization method. We employ large-scale matrix diagonalization and realistic effective single-particle potentials. The influence of the surface potential on the adiabatic evolution of the wave function and the resonance parameters as a function of the distance d from the surface have been investigated. Application to the ground state H(1s) yields significant differences for the position and width of the resonance compared to previously available data. The applicability of semiclassical theory for resonance parameters is tested and the role of over-barrier transitions is highlighted.