Dynamics of He Double Ionization in the Non-Perturbative Regime: The Reduction to an Effective Three-Particle Problem


Double ionization of He by 3.6 MeV u -1 Au 53+ impact is investigated in a kinematically complete experiment using an integrated multi-electron recoilion momentum spectrometer (reaction microscope). Surprisingly, the final-state correlation between the recoiling He 2+ target ion momentum and the momenta of both emitted electrons is found to be the strongest among the various two-body correlations. On this basis it is demonstrated that the four-body momentum balance can be reduced to a good approximation to an effective three-particle problem by considering the centre-of-mass motion of the two electrons instead of their individual momenta. Then, all essential dynamical features observed for single ionization earlier, like for example a strong forward-backward asymmetry in the longitudinal momentum balance resulting from the final-state interaction with the projectile, are naturally rediscovered. Moreover, important conclusions on the properties of the TS-2 double ionization mechanism are drawn.



Keywords and Phrases

Approximation theory; Electrodynamics; Electron emission; Electron transport properties; Ionization of gases; Kinematics; Perturbation techniques; Spectrometers; Center of mass motion; Forward-backward asymmetry; Helium double ionization; Multi-electron recoil ion momentum spectrometer; Non perturbative regime

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Article - Journal

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© 2002 Institute of Physics - IOP Publishing, All rights reserved.

Publication Date

01 Apr 2002