Coplanar symmetric (e, 2e) cross sections for krypton 4s ionization

Abstract

The triple-differential cross section for electron impact ionization of the 4s orbital of krypton (binding energy 27.5 eV) has been measured in coplanar symmetric kinematics. The experimental results are presented for outgoing electron energies of 85, 50, 20, 10 and 4 eV. The results are compared with two distorted wave Born approximation calculations; the influence of post-collision interaction (PCI) on the cross sections is investigated by incorporating correct final state boundary conditions in one of the calculations. The influence of PCI is found to be very important at the lower energies. Inclusion of the three-body final state boundary conditions improves the agreement between theory and experiment, but there are still significant discrepancies, indicating that additional physical effects (such as higher-order interactions) are important at lower energies.

Triple differential cross section in (e, 2e) collisions for sodium in a coplanar symmetric geometry

“…Besides the variation trends for the forward and backward scattering peaks, at incident energies of 35 These similar bumps were also observed in the TDCS for s valence orbitals of Mg [15], K [15], Ca [15], Ne [35], Ar [36], and Kr [37], but not observed in He [38,39]. Considering the similarities and differences in electronic structures of these atoms, we calculated the TDCS of Na by switching off the interaction between active electron and passive s or p electrons from the distorting potentials.…”

An energetic (e, 2e) reaction away from the Bethe ridge: recoil versus binary

“…The noble gas atoms are attractive candidates for this research because of a relatively simple closed-shell electronic structure. In the past decade, the (e,2e) reaction, in both the symmetric and the non-symmetric kinematics, was measured extensively on Ne, Ar and Xe valence shells at an incident energy typically 10 times larger than the corresponding ionization potential (Haynes and Lohmann 2000, 2001a,b, Biava et al 2002, Haynes et al 2003, Stevenson et al 2005, 2009, Stevenson and Lohmann 2006. Various theoretical models were applied to describe these experimental data: the distorted wave Born approximation 4 Author to whom any correspondence should be addressed.…”

Effects of dynamical screening on single ionization of sodium by electron impact in doubly symmetric geometry

“…The final state is reduced to a three-body system by assuming that the residual ion (Na + ) acts as a point charge on the two escaping electrons. Such an approximation is, of course, not generally adequate [10,11], but it allows us to apply the DS3C or 3C model to the complex case of ionizing a many-electron atom such as sodium in the present case or carbon [13], argon [14], and neon [15], or a complex molecule such as water [16]. We might expect that our DS3C or 3C model would yield at least qualitatively correct results, for instance, concerning the positions of the binary and recoil lobes maxima.…”

“…It should be noted that these final states are an asymptotic solution of the three-body problem and contain the electron-electron postcollision interaction (PCI) effect to all orders of perturbation theory [9]. Haynes et al [10] and Prideaux and Madison [11] have recently generalized the 3C model of Brauner et al [7] for heavier targets (the natural extension of the 3C wave function to the case of arbitrary central potentials). Although their results illustrate some agreement with experiment, the agreement between experiment and theory did not lead to the expected accuracy, particularly for the higher energy argon coplanar symmetric case [11].…”