Doubly-Excited ^1,3S^e, ^1,3P⁰, ^1,3D^e, ^1,3F⁰ and ^1,3G^e Resonances States of Two-Electron Atoms below the N = 3 – 8 Hydrogenic Thresholds

M.T. Gning^1, and I. Sakho¹

¹Department of Physics Chemistry, UFR Sciences and Technologies, University of Thies, Thies, Senegal

Cite this paper:
M.T. Gning and I. Sakho. Doubly-Excited ^1,3S^e, ^1,3P⁰, ^1,3D^e, ^1,3F⁰ and ^1,3G^e Resonances States of Two-Electron Atoms below the N = 3 – 8 Hydrogenic Thresholds. International Journal of Physics. 2022; 10(1):23-48. doi: 10.12691/ijp-10-1-2

Abstract

In this paper we present accurately calculated data on the resonance parameters (resonance energy and excitation energies) of the doubly excited singlet and triplet states ^1,3S^e, ^1,3P⁰, ^1,3D^e, ^1,3F⁰ and ^1,3G^e of helium and helium-like ions (Z = 2 – 10) located below the hydrogenic thresholds N = 3 – 8, using the variational method of the Screening Constant per Unit Nuclear Charge (SCUNC) formalism. These energies are calculated using special form wave functions of the Hylleraas type and a real Hamiltonian. The results obtained are in very good agreement with the experimental and theoretical values available in the literature. The results for the energies of the doubly excited ^1,3S^e, ^1,3P⁰, ^1,3D^e, ^1,3F⁰ and ^1,3G^e states associated with hydrogenic thresholds up to N = 8 listed for the first time in this paper may provide a useful guideline for future experimental and theoretical studies in the autoionization states of two-electron systems.

Keywords:
helium-like systems energy resonances excitation energy screening constant by unit nuclear charge (SCUNC) doubly excited states hylleraas type wave function

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