Second-Order Corrections to the Fine Structure of Helium. II. Contributions from 1P and 3D Intermediate States
The contributions from the three spin-dependent Breit operators in second-order perturbation theory are calculated when the symmetries of the intermediate states are odd 1P or 3D. Standard Hylleraas expansions with up to 165 terms are used for the perturbations of the wave functions. The large interval of the fine structure of the 23P level in helium is increased by 2.17(2)×10-4 cm-1 by 1P, and by 0.0089(6)×10-4 cm-1 by 3D. Two methods for handling angular integration over D tensors are described.