Low-energy e-H₂ scattering: Separation of dissociative attachment and dissociation channels

Electron impact dissociation and dissociative attachment (DA) via the ²Σ_u⁺ shape resonance in e-H₂ collisions is treated by the quasiclassical version of the nonlocal resonance theory. Optical theorem is applied to analyze all the energetically accessible channels. Collisionally induced dissociation and dissociative attachment cross sections for vibrationally or rotationally excited H₂ molecule are presented in the electron energy range up to 5 eV. It is shown that the DA cross sections we published recently [Phys. Rev. A 61, 052705 (2000)] in fact represent the sum of the cross sections for the DA and dissociation processes in the energy range above the dissociation threshold.