Scattering variational calculation of characteristics of doubly excitedSstates in helium

Positions and widths of the lowest-lying ¹,3S resonances in helium are presented along with their oscillator strengths to the singly excited ¹,3P ^∘{} states (1s-np,n=2,4). The background differential oscillator strength from the P states to the S continuum is also found and is very small. The resonances are described by an expansion of square-integrable functions in hyperspherical coordinates; the continuum is treated by using positive-energy Coulomb functions, and the two are brought together by a scattering variational principle. Computed branching ratios for these states indicate which state might be seen as a satellite line in an ion-atom collision.