# The two-electron atomic systems. S-states

## Description

Abstract A simple Mathematica program for computing the S-state energies and wave functions of two-electron (helium-like) atoms (ions) is presented. The well-known method of projecting the Schrödinger equation onto the finite subspace of basis functions was applied. The basis functions are composed of the exponentials combined with integer powers of the simplest perimetric coordinates. No special subroutines were used, only built-in objects supported by Mathematica. The accuracy of results and computa... Title of program: TwoElAtom-S Catalogue Id: AEFK_v1_0 Nature of problem The Schrödinger equation for atoms (ions) with more than one electron has not been solved analytically. Approximate methods must be applied in order to obtain the wave functions or other physical attributes from quantum mechanical calculations. Versions of this program held in the CPC repository in Mendeley Data AEFK_v1_0; TwoElAtom-S; 10.1016/j.cpc.2009.09.012 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018)