Positive and negative hydrogen ion reflections of low-energy atomic and molecular hydrogen ion beam from HOPG and Mo surfaces.

Positive and negative hydrogen ion reflections from surfaces by injecting singly charged hydrogen ion beams show a clear difference between atomic and molecular ion injections at low energy and grazing incidence. The intensity ratio of reflected negative to positive ions H ^- /H ⁺ increased as the incident beam energy per nucleon decreased only when molecular ion beams are injected. It implies that negative ions are more produced upon beam-surface interaction when molecules are injected. A possible reason was discussed in terms of difference in the negative ion production processes between atomic and molecular ions.