Eur. Phys. J. B (2016) 89: 190
https://doi.org/10.1140/epjb/e2016-70194-3

Regular Article

On accurate computations of slowly convergent atomic properties in few-electron ions and electron-electron correlations

¹ Department of Applied Mathematics, University of Western Ontario, London, N6H 5B7 Ontario, Canada
² Department of Chemistry, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, A1C 5S7, Canada

^a e-mail: afrolov@uwo.ca

Received: 29 March 2016
Received in final form: 12 June 2016
Published online: 5 September 2016

Abstract

We discuss an approach to accurate numerical computations of slowly convergent properties in two-electron atoms/ions which include the negatively charged Ps⁻ (e⁻e⁺e⁻) and H⁻ ions, He atom and positively charged, helium-like ions from Li⁺ to Ni²⁶⁺. All these ions are considered in their ground 1¹S-state(s). The slowly convergent properties selected in this study include the electron-nulceus (r^2k_eN) and electron-electron (r^2k_ee) expectation values for k = 2, 3, 4 and 5.