INFLUENCE OF HELIUM SURFACE ON PHOTODETACHMENT OF NEGATIVE IONS

The photodetachment of H- on the surface of helium is investigated by quantum and semiclassical Green function approaches. It is found that a new sinusoidal oscillation is introduced in the photodetachment cross-section because of the existence of helium surface. Both quantum and semiclassical approaches give similar results but with minor difference when the photon energy is higher than the surface potential. The new oscillation is formed due to transmissions and reflections of the photodetached electronic waves on helium surface. It provides a simple system to test quantum reflection.