Publikace ÚTF

The regularized method of analytic continuation is used to study the low-energy negative-ion states of
beryllium (configuration 2s2εp 2P ) and magnesium (configuration 3s2εp 2P ) atoms. The method applies an
additional perturbation potential and requires only routine bound-state multi-electron quantum calculations. Such
computations are accessible by most of the free or commercial quantum chemistry software available for atoms
and molecules. The perturbation potential is implemented as a spherical Gaussian function with a fixed width.
Stability of the analytic continuation technique with respect to the width and with respect to the input range of
electron affinities is studied in detail. The computed resonance parameters Er = 0.282 eV,  = 0.316 eV for the
2p state of Be− and Er = 0.188 eV,  = 0.167 for the 3p state of Mg− agree well with the best results obtained
by much more elaborate and computationally demanding present-day methods