Electron‐impact single ionization cross sections of helium isoelectronic systems

Abstract

ABSTRACT:-are calculated using a recently propounded parameter-free relativistic binary encounter (RBEA) model, which remains valid up to the relativistic energy domain. Our RBEA results are compared with those of the Coulomb-Born (CB) approximation, distorted wave Born approximation (DWBA), relativistic two-potential DWBA (RTPD), the simple empirical model of Brenshtam et al. (BRY), and the model of Deutsch and Märk (DM) along with the available experimental data. The RBEA model, while keeping the comparable predictive power of cross sections, is found to overcome the limitations of the empirical BRY and DM models with their fitting parameters, and the quantum mechanical CB, DWBA, and RTPD theories with arduous and lengthy calculations.

Calculations of electron-impact single-ionization cross sections of helium isoelectronic systems

“…tions [42] and the results of RBEB [28], BRY [16], relativistic DM [33], RBEA [20], DWBA [34], and RTPD [5]. The RBEB, siBED, QIBED, and RQIBED results are almost identical and agree very well with the findings of the experiment and the RTPD calculations.…”

“…The solid curve, solid curve with pluses, and solid curve with solid diamonds denote, respectively, the siBED, QIBED, and RQIBED predictions. The broken curve with solid circles, broken curve with open triangles, broken curve with open diamonds, and broken curve with open squares are, respectively, the calculations from the BRY [16], relativistic DM [33], RBEA [20], and RBEB [28] models. The broken curve is DWBA [34].…”

“…2, we present the calculated cross sections for Li + from siBED, QIBED, and RQIBED, experimental results [43,44], and findings from the RBEB [28], BRY [16], DM [33], and RBEA [20] models, and from the CB [36] and DWBA [34] theories. The large difference between the siBED and QIBED cross sections shows that the contribution from the ionic correction is significant and the siBED is inadequate for an ionic target.…”

“…Vriens [18] modified the BEA with the inclusion of an exchange term and a term denoting the interference between the exchange and direct terms. Uddin et al infused a relativistic factor in the Vriens' model to propose as the parameter-free RBEA model and to apply to the hydrogen [19] and helium [20] isoelectronic systems. Both the DM model (Deutsch and Märk [21]) and the binary-encounter dipole (BED) model of Kim and Rudd [22] have been widely applied to electron impact ionization of atoms and molecules.…”

“…To augment the comparative study, we also calculate the cross sections employing RBEB [28], BRY [16], relativistic DM [33] and RBEA [20], and use the results of the distorted wave Born approximation (DWBA) [34,35], Coulomb-Born (CB) approximation without [36] or with exchange (CBX) [37], and relativistic two-potential DWBA (RTPD) referred to as TPDW01 in Ref. [5].…”