Angle-energy distributions of Penning ions in crossed molecular beams. IV. He*(21 S,2 3S)+H2-->He+H2+ +e-.

Relative doubly differential cross sections for the Penning ionization of H(2) by spin-state-selected metastable He (1s2s) are reported at center-of-mass collision energies E of 3.1 and 4.2 kcal/mol in a crossed supersonic beam experiment employing a rotatable mass spectrometer detector.