Excitation of the Q₁¹Σ_g⁺doubly excited state of H₂by electron impact

Abstract

400 eV electrons were used to excite the autoionizing state Q 1 1 + g of H 2 . The relative cross section was measured as a function of: (1) the angle between the internuclear axis and the momentum transfer vector of the collision; and (2) energy loss for a fixed orientation of the molecular axis in the laboratory frame. In the first set of measurements electrons scattered at 18 • with an energy loss of 29 eV were detected in coincidence with a 2 eV H + ion resulting from dissociation following autoionization. The angular distribution of the 2 eV ions was recorded and fitted to calculated values. A maximum was found when the internuclear axis was aligned with the momentum transfer vector. Secondly, the relative yield of 2 eV H + ions was measured as a function of energy loss in the electron-H 2 collisions. Energy loss ranged from 23 to 35 eV. The lowest lying Q 1 1 + g , 1 + u and 1 g were included in the calculated fit to the data.

Fivefold differential cross sections for ground-state ionization of aligned H2 by electron impact

“…46,47 In our experiment, the momentum transfer is calculated individually for each collision. As mentioned earlier, we have observed that the momentum transfer q ជ is a preferred alignment for the ionizing collision.…”

Accurate Born-Oppenheimer potentials for excited $Σ^{+}$ states of the hydrogen molecule

“…Accurate potentials are also important for studying gerade/ungerade mixing effects [23] beyond the BO approximation. Ultimately, accurate BO potentials may serve as a useful benchmark for less precise computational methods, electronion scattering experiments and numerous other applications [24,25,26]. We note that many previous calculations often come without estimation of uncertainties, making definitive comparisons rather difficult.…”

Modified two-centre continuum wavefunction: application to the dissociative double ionization of H2by electron impact

“…The coincidence detection techniques, measuring the momenta of fragments emerging from atomic collision processes and especially from dissociative ionization experiments of diatomic species by electron impact, are now undergoing a very rapid development [2][3][4][5]. This type of coincidence detections has been already performed in collision experiments involving the multiply charged ionic projectiles and the hydrogen molecule [6][7][8][9].…”