COMPLEX-ROTATION CALCULATIONS FOR DOUBLY EXCITED STATES (Nℓ Nℓ) 2S+1Lᴨ [(2≤N≤ 3 ) ( 3 ≤N≤4) (0 ≤ ℓ ≤ 2 ) AND ( 0 ≤ ℓ ≤ 2)] OF HELIUM ISOELECTRONIC SERIES

In this paper, we report the energies and resonant widths of the [(2s3s ¹S^e and 2s3s ³S^e) (2s4s ¹S^e and 2s4s ³S^e) (2s3p ¹P⁰ and 2s3p ³P⁰) (2s4p ¹P⁰ and 2s4p ³P⁰) (2p3p ¹D^e and 2p3p ³D^e) (2p4p ¹D^e and 2p4p ³D^e) (3s4s ¹S^e and 3s4s ³S^e) (3s4p ¹P⁰ and 3s4p ³P⁰) (3p4p ¹D^e and 3p4p ³De)  (3d4d ¹G^e and 3d4d ¹G^e)] Doubly Excited States of Helium isoelectronic series with nuclear charge Z (2 ≤ Z ≤ 10).Calculations are performedusing the Complex Rotation Method (CRM) in the framework of a variational procedure. The purpose of this study required a new correlated hydrogenic radial wave function combined with a Hylleraas wave function. The study leads to analytical expressions which are carried out under special MAXIMA computational program. This proposed variational procedure, leads to accurate results in good agreement with available other theoretical results.The present accurate data may be a useful guideline for future experimental and theoretical studies in the (Nâ„“ Nâ„“) ^2S+1L^á´¨systems.