Single ionization of helium by 102 eV electron impact: three-dimensional images for electron emission

Dürr, M., Dimopoulou, C., Dorn, A., Najjari, B., Bray, I., Fursa, D.V., Chen, Z., Madison, D.H., Bartschat, Kn and Ullrich, Jn (2006) Single ionization of helium by 102 eV electron impact: three-dimensional images for electron emission. Journal of Physics B: Atomic, Molecular and Optical Physics, 39 (20). pp. 4097-4111.

Abstract

Single ionization of helium by 102 eV electron impact has been studied by measuring the momentum vectors of all final-state particles, i.e., two electrons and the He + ion, with an advanced reaction microscope. Fully differential cross sections for asymmetric scattering geometry, which have been normalized to an absolute scale, have been obtained covering a large range of emission angles for the emitted low-energy (E ≤ 15 eV) electron and different scattering angles for the fast electron. Strong electron emission out of the projectile scattering plane is confirmed for electron impact, as was observed before for heavy-ion impact ionization. The data are compared with theoretical predictions from a three-Coulomb wavefunction model, first-order and second-order distorted-wave approaches, as well as a convergent close-coupling calculation.