Inhibition of H- production in the foil breakup of fast H2+

Comparison of emergent H- yields for incident H+ and H2+ beams of the same velocity (0.4, 0.8, and 1.2 MeV/amu) traversing carbon foils of 1--8 μg/cm2 shows that, per incident proton, the H- yield from H2+ is generally inhibited, in striking contrast to the enhanced H0 yield previously observed. An explanation of the major inhibition effect is given in term of the Landau-Zener approximation to a ''one-passage'' charge transfer from the H- to its H+ breakup partner