Variational Calculations of Energies of the (2<i>snl</i>) <sup>1,3</sup><i>L<sup>π</sup></i> and (2<i>pnl</i>) <sup>1,3 </sup><i>L<sup>π</sup></i>Doubly Excited States in Two-Electron Systems Applying the Screening Constant per Unit Nuclear Charge

Abstract

In this paper, resonance energies and excitation energies of doubly 2sns 1,3 S e , 2snp 1,3 P 0 , 2pnp 1,3 D e , 2pnd 1,3 F 0 and 2pnf 1,3 G e excited states of the helium isoelectronic sequence with Z ≤ 10 are calculated. Calculations are carried out in the framework of the variational procedure of the formalism of the Screening Constant per Unit Nuclear Charge (SCUNC). New correlated wave function of Hylleraas type is used. Precise resonance and excitation energies are tabulated and good agreement is obtained when a comparison is made with available literature values.