He+O2 collisions at low keV energies

The direct scattering in He0+O2 collisions is studied at low keV energies and scattering angles 0<θ<2 deg. Time-of-flight techniques are used to identify the states excited. The experimental techniques have previously been described. To date the authors have reported on H0+N2 collisions and also on H0+H2 and O2. A striking characteristic of the H0 collisions is the weakness of the electronically elastic channel even at the smallest scattering angles. In He+O2 the authors find elastic scattering to be the dominant small angle process. The probability of electronically elastic scattering is greater than 0.5 at angles less than 1.0 deg and falls to 0.1 at 2.0 deg. The spectra show an inelastic peak at a 6 eV energy loss which is attributed to He+O2 → He+O2* → He+O(3P) + O(3P). A broad structure with a maximum near 16 eV is seen at larger angles and is attributed in part to excitation resulting in dissociating states of O2. Excitation of the He is found to be at the energies and angles studied. Additional results will be presented and interpreted