We study destabilization of an atom in its ground state with decrease of its nuclear charge. By analytic continuation from bound to resonance states, we obtain complex energies of unstable atomic anions with nuclear charge which is less than the minimum "critical" charge necessary to bind N electrons. We use an extrapolating scheme with a simple model potential for the electron which is loosely bound outside the atomic core. Results for O-- and S-- are in good agreement with earlier estimates. Alternatively, we use the Hylleraas-basis variational technique with three complex nonlinear parameters to find accurately the energy of two-electron atoms as the nuclear charge decreases. Results are used to check the less accurate one-electron model.
Draft of a possible paper, pdf
Reformatted paper, TeX and PDF.
Revised and shortened version that was finally accepted, TeX and PDF.
Final version, PDF file from the journal.
Mathematica programs and results of calculations
Variational calculations of the energy for helium isoelectronic series as a function of the nuclear charge on Hylleraas basis set:
Back to Results of work in Purdue University.
Designed by A. Sergeev.