Complex-coordinate calculations for doubly excited states of two-electron atoms

Abstract

Doubly excited states of helium sequence ($Z=1\ensuremath{-}10$) are investigated by a complex-coordinate method. Some lower-lying $^{1}S^{e}$ and $^{1,3}P^{o}$ states below the $N=2$ hydrogenic thresholds are calculated by the use of Hylleraas-type wave functions. Results are compared with recent calculations and experiments.