Physical Review A
Accurate eigenvalues and radiative lifetimes are obtained for the bound 2p2 P3 and 2p3p P1 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 1s2pP3-2p2 P3 and 1s3pP1-2p3pP1 transitions in helium are, respectively, 320.31 and 308.97 Å. Lines have been observed in helium at 320.39 and 309.04 Å. © 1970 The American Physical Society.
Drake, Gordon W. F. and Dalgarno, A.. (1970). 2p2 P3 and 2p3p P1 states of the helium isoelectronic sequence. Physical Review A, 1 (5), 1325-1329.