The relative cross sections of Ar double ionization by electron impact have been measured in an (e, 3e) experiment at low incident energy E0 = 561.4 eV, at a scattering angle a = 6.5° and with equal energy sharing among the two 'ejected' electrons, Eb = Ec = 9 eV. The experimental results are compared with calculations in the first Born approximation, which include the shake-off and two-step 1 mechanisms in the target- projectile interaction. The symmetry breaking about the direction of the momentum transfer and the appearance of a small feature near the main ones show that the non-first-order effects (such as two-step 2 mechanism) play an important role. These effects are enhanced in the present experiments with respect to the former ones (El Marji et al 1997 J. Phys. B: At. Mol. Opt. Phys. 30 3677) with higher collision energy, E0 = 5563 eV, which is in agreement with an earlier theoretical estimate by McGuire.
Dynamics of the double ionization process by electron impact : Ar (e, 3e) experiments at low collision energy
2002
Abstract
The relative cross sections of Ar double ionization by electron impact have been measured in an (e, 3e) experiment at low incident energy E0 = 561.4 eV, at a scattering angle a = 6.5° and with equal energy sharing among the two 'ejected' electrons, Eb = Ec = 9 eV. The experimental results are compared with calculations in the first Born approximation, which include the shake-off and two-step 1 mechanisms in the target- projectile interaction. The symmetry breaking about the direction of the momentum transfer and the appearance of a small feature near the main ones show that the non-first-order effects (such as two-step 2 mechanism) play an important role. These effects are enhanced in the present experiments with respect to the former ones (El Marji et al 1997 J. Phys. B: At. Mol. Opt. Phys. 30 3677) with higher collision energy, E0 = 5563 eV, which is in agreement with an earlier theoretical estimate by McGuire.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
