Experimental and theoretical study of electron-impact ionization plus excitation of aligned H₂

We report quadruple differential cross sections for electron-impact ionization of H₂ with simultaneous excitation of the H⁺₂ ion which will immediately dissociate. The alignment of the molecule is determined by detecting the emitted proton. The first measurements of this type were recently reported (2013 Phys. Rev. A 88 062705). Here we report measurements with much better angular resolution using the COLTRIMS method. Experimental results are compared with molecular 4-body distorted wave calculations and reasonably good agreement between experiment and theory is found.