Electron impact double ionization of neon, argon and molecular nitrogen: role of the two-step mechanism

C Li (1) , A Lahmam-Bennani (1) , E M Staicu Casagrande (1) , C Dal Cappello (2)

1 ISMO - Institut des Sciences Moléculaires d'Orsay
2 IJB - Institut Jean Barriol

Recent measurements of the (e, 3-1e) four-fold differential cross sections (4DCS) for double ionisation of helium are here extended to more complex targets, namely neon, argon and molecular nitrogen. The previous observations of large angular shifts in the experimental 4DCS distributions with respect to the momentum transfer axis and the existence of structures in these distributions are found to similarly hold here. For the three investigated targets, the experimental data are compared with the kinematical analysis previously given to describe the second order, 'two-step 2 ' double ionisation mechanism. Such comparison confirms our interpretation which allows relating the observed shifts and structures in the intensity distributions mostly to the 'two-step 2 ' mechanism, which is shown to predominate over the first-order 'shake-off ' and 'two-step 1 ' mechanisms under the present kinematics. The experimental data are also compared to the predictions of a first Born and a second Born model, showing a rather mixed agreement.

Mots clés: 34.80.Dp; 34.50.Fa; 34.80.-I; 34.10.+x

C Li, A Lahmam-Bennani, E M Staicu Casagrande, C Dal Cappello. Electron impact double ionization of neon, argon and molecular nitrogen: role of the two-step mechanism. Journal of Physics B: Atomic, Molecular and Optical Physics, 2011, 44 (11), pp.115201. ⟨10.1088/0953-4075/44/11/115201⟩. ⟨hal-00625575⟩