Charge distribution of He states, excited by electron capture in He+ (26 keV) – He collisions
1 Institute of Experimental Physics, University of Gdańsk, ul. Wita Stwosza 57, 80-952 Gdańsk, Poland
2 Institüt für Optik und atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany
Received: 8 June 2013
Revised: 9 August 2013
Published online: 23 October 2013
Using anticrossing spectroscopy we investigated one-electron capture in He+ (26 keV) – He collisions. The intensity of the triplet line λ (1s4l 3D → 1s2p 3P) ≈ 447.2 nm emitted by the fast atoms was measured as a function of an external electric field in the collision volume varied from −30 kV/cm to +30 kV/cm. The radiative decay of excited He atoms in an almost field-free region outside the collision volume was observed. The highly asymmetric intensity function could be reproduced theoretically using the density-matrix formalism. It indicates that the excited He atoms are in a state with a highly forward-backward asymmetric charge distribution, immediately after the charge-exchange collision.
© EDP Sciences, Springer-Verlag, 2013