We have calculated triply differential cross sections (TDCS) and doubly differential cross sections (DDCS) for single ionization of ${\mathrm{H}}_2$ by 75-keV proton impact using the molecular three-body distorted-wave–eikonal initial-state (M3DW-EIS) approach. Previously published measured DDCS (differential in the projectile scattering angle and integrated over the ejected electron angles) found pronounced structures at relatively large angles that were interpreted as an interference resulting from the two-centered potential of the molecule. Theory treating ${\mathrm{H}}_2$ as atomic H multiplied by a molecular interference factor only predicts the observed structure when assumptions are made about the molecular orientation. Here we apply the M3DW-EIS method, which does not rely on such an ad hoc approach, but rather treats the interference from first principles.

• Received 13 December 2010

DOI:https://doi.org/10.1103/PhysRevA.83.032712