Electron-Proton Coincidence in Electron Impact Dissociation of H_2
Abstract
We have recently completed an experiment of electron scattering from molecular hydrogen. The scattered electron is detected at a selected angle and with a selected energy loss. Atomic hydrogen ions ejected by excited H_2^+ ions are detected at a selected angle and with a selected energy. The scattered electron and H^+ ion are measured in coincidence. Within the limits of the axial recoil approximation the H^+ ion leaves the interaction region along the line of the internuclear axis at the time of the excitation process. The detection of the scattered electron at a specific scattering angle and energy loss defines the scattering plane and the momentum transfer vector. The coincidence measurement of the H^+ ion with the scattered electron yields the relative cross section of the excitation of a particular H_2^+ state as a function of the orientation of the molecular axis relative to the momentum transfer vector K. In this report, 400 eV electrons are scattered at 18 degrees from the original beam direction with an energy loss of 36 eV. This gives Ka_o=1.68 at 73 degrees. H^+ ions with an energy of 7.6 eV are detected at selected angles on the opposite side of the beam from the electron detector. The combination of the energy loss and the dissociation energy selects H^+ ions from the 2pσu state of H_2^+ for the coincidence measurement.
- Publication:
-
APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts
- Pub Date:
- May 1998
- Bibcode:
- 1998APS..DMP..OP45M