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

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 Ni. All these ions are considered in their ground 1S-state(s). The slowly convergent properties selected in this study include the electron-nulceus ( r ) and electron-electron ( r ) expectation values for k = 2, 3, 4 and 5. [ABSTRACT FROM AUTHOR]