Triply differential (e,2e) cross sections for He from threshold to 50 eV above

Authors

C. Pan, University of Nebraska - Lincoln
Anthony F. Starace, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

October 1993

Comments

Published in Journal de Physique IV: Colloque C6, supplément au Journal de Physique II, Volume 3, novembre 1993. Published by EDP SCiences. Used by permission.

Abstract

Distorted wave calculations of the triply differential cross sections for electron-impact ionization of He are presented for electrons sharing ≤ 50 eV excess energy (E_x) and having the coplanar, θ₁₂ = π geometry. The results are in good agreement with absolute experimental measurements of T. Rösel et al. [Phys. Rev. A 46 (1992) 2539-2552] and of A. J. Murray, M. B. Woolf, and F. H. Read [J. Phys. B 25 (1992) 3021-3036]. For final state electrons sharing 2 eV excess energy equally, many-body perturbation theory corrections to the authors' first order (e,2e) triply differential cross sections [Phys. Rev. A 45 (1992) 4588–4603] are also presented. These results indicate that singlet-triplet interchannel coupling effects in the final state are very significant; that initial state correlations are significant near the perpendicular plane, i.e., θ₁ = θ₂ = π/2 ; and that the polarization effects we include are insignificant. Finally, comparison of our first order results with the semiclassical quanta1 theory results of D. S. F. Crothers [J. Phys. B 19 (1986) 463–483] shows excellent agreement for excess energies E_x ≥ 2 eV and for θ₁ = θ₂ = π/2; for E_x < 2 eV, the two results diverge as E_x → 0, indicating that experimental tests of the Wannier-Peterkop-Rau theory of three-body Coulomb breakup should be carried out in this energy region.