Variational nonrelativistic calculations for the (2pnp)1,3Pestates of two-electron atomic systems

The Rayleigh-Ritz variational method utilizing the Sturmian-Legendre basis set has been applied to doubly excited P states of even parity of the He I isoelectronic sequence in order to obtain the nonrelativistic energy positions of the lowest lying states. The states themselves are of physical interest to study since they are metastable against autoionization within the LC coupling approximation. The energy positions are of importance as initial states for electronic transitions now being studied by the beam-foil technique. For helium the wavelengths of possible allowed transitions and the corresponding wavefunctions are given. A comparison of the results with those obtained by other theoretical calculations has also been included.