2p2P3and2p3pP1States of the Helium Isoelectronic Sequence

Abstract

Accurate eigenvalues and radiative lifetimes are obtained for the bound $2p^2{}_{}{}^3{}_{}{}^{}P$ and $2p3p{}_{}{}^1{}_{}{}^{}P$ states of the heliumlike ions He i to Ne ix. A high-order $Z$-expansion perturbation procedure is used that does not require the explicit solution of perturbation equations. The results are compared with variational calculations. The predicted wavelengths of the $1s2p{}_{}{}^3{}_{}{}^{}P-2\mathrm{}{p}^2{}_{}{}^3{}_{}{}^{}P$ and $1s3p{}_{}{}^1{}_{}{}^{}P-2p3p{}_{}{}^1{}_{}{}^{}P$ transitions in helium are, respectively, 320.31 and 308.97 Å. Lines have been observed in helium at 320.39 and 309.04 Å.