Critical minima in elastic electron scattering from argon

Abstract

Relativistic ab initio calculations of both low-and high-angle critical minima in the differential cross sections are presented. The theoretical approach is based on the Dirac-Hartree-Fock method. Exchange between incident and target electrons is calculated exactly. Target polarization is described by ab initio potential taken from relativistic polarized orbital calculations. The position of our critical minima (39.3 eV, 68 •) and (39.5 eV, 141 •) agree well with recent measurements performed by Panajatović et al.

e± Ar scattering in the energy range 1 eV ≤ E i ≤ 0.5 GeV

“…A similar behavior is also noticed in figure 13(f), where the DCS is much lower at 38.21 eV than at E i =36.0 and 40.0 eV. Table 1 gives a comparison of our computed positions of the deepest minima in the DCS with those of six experimental [15,59,81,84,102,104] and eight other theoretical [15,22,32,34,88,101,103,105] predictions. It is evident from this table that the angular positions of the deepest DCS minima reported here produce an overall good agreement with the experimental data.…”

“…As the DCS values are usually reported with a step of 5°in the literature, one may infer that the angular position of any CM is not determined better than ±2.5°. The maximum deviation in angular position between our result and experiment is 141 143. taken from [22], and to the uncertainty in the theoretical values computed from the relativistic approximation of [34].…”

“…Since the first electron-atom scattering experiments in 1931 [5], many theoretical and experimental studies on e ± -Ar have been available in the literature [6][7][8]. Apart from these investigations, the experimental works of Ranković et al [9], Zecca et al [10], Jones et al [11], Kurokawa et al [12], Cho and Park [13], Hargreaves et al [14], Milosavljević et al [15], Mielewska et al [16] and Gilbert et al [17], and the theoretical calculations of Ranković et al [9], Bartschat et al [18], Green et al [19], Fursa and Bray [20], Jones et al [11], Mohan et al [21], McEachran and Stauffer [22], Bote et al [23], Gargioni and Grosswendt [4], Adibzadeh and Theodosiou [24], Yousif Al-Mulla [25], Jablonski et al [26], Salvat [27], Stepanek [28], Blanco and García [29,30], Paikeday and Alexander [31], Kelemen [32], Bartlett and Stelbovics [33], Sienkiewicz et al [34] and Pandya and Shah [35], are worth mentioning among the important works.…”

An optical potential method for elastic electron and positron scattering from argon

“…More recently, Sienkiewicz et al (2001Sienkiewicz et al ( , 2003 have calculated the position of the critical minima for electron scattering using a fully relativistic potential scattering method including the static and polarization interactions. They also treat exchange with the incident electron exactly.…”

Relativistic multiconfiguration method in low-energy scattering of electrons from argon atoms

“…Saha (1991) based on the multiconfiguration Hartree-Fock method. Relativistic Dirac-Fock method, in connection with model polarization potentials was used by Sienkiewicz et al (2001).…”