Abstract
Two electrons at the threshold of ionization represent a severe test case for electronic structure theory. Variational methods can yield highly accurate energies, but may be less accurate for other operators of interest. A pseudospectral method yields very accurate expectations values for the two-electron ion with nuclear charge at and close to the critical value which yields zero ionization energy. As an illustration, the ground-state density is calculated and an extremely accurate parametrization is given. Other components in Kohn-Sham density functional theory are also calculated, and the efficacy of approximations is discussed.
- Received 8 August 2014
- Revised 9 February 2015
DOI:https://doi.org/10.1103/PhysRevA.91.032501
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