Elastic scattering of electrons from Xe,Cs+, andBa2+

Abstract

Relativistic many-body perturbation theory is applied to study the elastic scattering of electrons from xenon and from the xenonlike ions Cs+ and Ba +, below their respective inelastic thresholds. The quasiparticle equation for the electron scattering wave function is solved in second-order perturbation theory starting from the Hartree-Fock approximation. Phase shifts for partial waves with 8 = 0 -5 are determined as functions of electron momentum for each ion. The theoretical elastic scattering cross section for xenon is found to be in agreement with experiment, showing a Ramsauer-Townsend minimum below 1 eV. Agreement with experiment is also found for difFerential cross sections and scattering asymmetry functions for xenon. Differential cross sections and scattering asymmetry functions for Cs+ and Ba + are predicted at 10 eV.

Large Angle Elastic Scattering of Electrons from Ar+

“…A recent many-body calculation at 10 eV predicts strong variation in large angle DCS for Cs+ due to the inclusion of polarization, as well as illustrating the quite different nature of the scattering to that observed from the isoelectronic neutral atom Xe [6].…”

“…Neither Szydlik, Kutcher, and Green nor Manson, either explicitly or implicitly, take account of the dynamic perturbation of the electronic charge cloud of the ion due to the electric field of the approaching electron. However, Johnson and Guet [6] in their treatment of elastic scattering from Cs+ at 10 eV note major differences between calculations for backscattering, with and without the inclusion of polarization effects. It is apparent that accurate reproduction of the present measurements requires a consideration of polarization and/or exchange.…”

Low-energy electron elastic scattering cross sections for excited Au and Pt atoms

“…Shape resonances are useful for interpreting electron-induced chemical processes resulting in negative ion production [3,25]. The Ramsauer-Townsend minima, manifesting the polarization of the atomic core by the scattered electron [31], are important among other things in the understanding of sympathetic cooling and the production of cold molecules from natural fermions [32]. Ground state atoms with low EA values are also required for the quenching of Rydberg atoms through collisions [33].…”

Many-Body Theory for Positronium-Atom Interactions

“…Many-body theory (MBT) is a powerful and systematic method of accounting for virtual excitations of both objects and the electron-positron correlation effects. It provided an accurate description of low-energy electron-atom scattering [23][24][25][26][27][28] and positron interaction with atoms [19,20,[29][30][31][32][33], with scattering cross sections, annihilation rates, and γ spectra all found to be in excellent agreement with experiment.…”