Experimental and theoretical cross sections for molecular-frame electron-impact excitation-ionization of D₂

We present both experimental and theoretical results for the dissociative ionization of D₂ molecules induced by electron impact. Cross sections are determined in the molecular frame and are fully differential in the energies and emission angles of the dissociation fragments. Transitions are considered from the X1Σ_g⁺ electronic ground state of D₂ to the 2sσ_g, 2pπ_u and 2pσ_u excited states of D₂⁺. The experimental results are compared to calculations performed within the molecular four-body distorted-wave framework to describe the multicenter nature of the scattering process. The cross sections reveal a dramatic dependence on both the alignment of the internuclear axis with respect to the direction of the projectile momentum and on the symmetry of the excited dissociating state which is energetically resolved.