VIBRATIONAL-STATES OF THE HYDROGEN ISOTOPES ON PD(111)

The ground and excited vibrational states for the three hydrogen isoto pes on the Pd(111) surface have been calculated. Notable features of t hese states are the high degree of anharmonicity, which is most promin ently seen in the weak isotopic dependence of the parallel vibrational transition, and the narrow bandwidths of these states, which imply th at atomic hydrogen is localized on a particular surface site on time s cales of 100 ps or more. Experiments to resolve ambiguities concerning the present system are suggested.