98 research outputs found
New (e,2e) Studies of Atomic and Molecular Targets
We report new coplanar (e,2e) measurements characterised by large energy transfer and close to minimum momentum transfer from the projectile to the target. Ionisation of the two-electron targets He and H2 is investigated under these particular kinematics. The experimental data are compared with the predictions of the most elaborate theoretical models. The obtained good agreement motivated us to extend our research to the case of more complex targets such as Ar. Comparison with the most elaborate models in the case of multi-electron targets is excellent. Destructive and constructive interference effects in the case of H2 are observed and discussed
Application of the -matrix Method to Faddeev-Merkuriev equation: beyond pseudostates
A version of the -matrix method for solving numerically the three-body
Faddeev-Merkuriev differential equations is proposed. This version allows to
take into account the full spectrum of the two-body Coulomb subsystem. As a
result, a discrete analog of the Lippmann-Schwinger equation is obtained which
allows to interpret correctly the three-body wave function in two-body domains.
The scheme is applied to calculations of the fully resolved absolute
differential cross sections for the HeHe and HeHe
reactions at small energy and momentum transfers. The results are in good
agreement with the experiment both in shape and in absolute value.Comment: 22 pages, 7 figure
Electron impact double ionization of helium from classical trajectory calculations
With a recently proposed quasiclassical ansatz [Geyer and Rost, J. Phys. B 35
(2002) 1479] it is possible to perform classical trajectory ionization
calculations on many electron targets. The autoionization of the target is
prevented by a M\o{}ller type backward--forward propagation scheme and allows
to consider all interactions between all particles without additional
stabilization. The application of the quasiclassical ansatz for helium targets
is explained and total and partially differential cross sections for electron
impact double ionization are calculated. In the high energy regime the
classical description fails to describe the dominant TS1 process, which leads
to big deviations, whereas for low energies the total cross section is
reproduced well. Differential cross sections calculated at 250 eV await their
experimental confirmation.Comment: LaTeX, 22 pages, 10 figures, submitted to J. Phys.
Comparative study of argon 3p electron-impact ionization at low energies
(c) 2001 The American Physical SocietyAn experimental and theoretical study of electron-impact ionization of the 3p orbital in argon is presented. The (e,2e) technique was used to measure the relative triple-differential cross section for this process in the coplanar asymmetric geometry. The experimental results were obtained at an incident electron energy of 113.5 eV, a scattering angle of 15°, and ejected electron energies of 10, 7.5, 5, and 2 eV. The experimental data are compared with a distorted-wave Born approximation (DWBA) calculation, and also with previous results for argon 3s ionization obtained under identical kinematic conditions. Discrepancies between the experimental and theoretical data are attributed to the effects of charge-cloud polarization and higher-order scattering processes, which are not incorporated in the DWBA calculation.Haynes, Matthew A. and Lohmann, Birgi
Electron–Electron Coincidence Studies on Atomic Targets: A Review of (e,2e) and (e,3e) Experiments
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