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.

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