DIRECT COLLISIONAL SCATTERING OF THE EXCITED HYDROGEN-ATOM - DOPPLER PROFILE ANALYSIS IN FAST AR+ ION COLLISIONS WITH ACETYLENE AND ETHYLENE

The Doppler profiles and translational energy distributions of H prod uced in Ar+-C2H2n (n = 2, 3) collisions have two major components. The slow component has a peak at about 10 eV and has been assigned as bei ng produced through the dissociative excitation of the parent molecule . The fast component has a large translational energy with its peak up to 100 eV, and should be produced through direct collision between Ar + and one of the H atoms in the molecule; the rest of the molecule is a spectator. The translational energy of the fast component is consist ent with a hard-sphere collision model.