Dissociative ionization of H2by fast protons: three-body break-up and molecular-frame electron emission

Highly differential cross sections have been obtained for dissociative single ionization of H 2 by 6 MeV proton impact by measuring the momentum vectors of the electron and the H + fragment in coincidence. The investigation of the momentum balance of the fragments along the projectile beam provided detailed insight into the four-particle dynamics, even though the H atom is not detected. Within the axial recoil approximation, molecular-frame angular distributions of emitted electrons have been determined for molecules oriented perpendicular to the projectile beam. They are compared with the predictions of a CDW-EIS calculation.