Mixing of LS configurations in terminating dipole series of H-

Resonant J(pi)=1(-) states of H- below the N=2 threshold are studied in a semiempirical coupled-channel calculation, in which fine structure and QED corrections are included exactly. This leads to the termination of the dipole series of Feshbach resonances and to increasing mixing between different L2S+1 states toward the end of the series. We predict a total of three resonances in the series dominantly of P-1(o) nature, and four resonances in the series dominantly of P-3(o) nature. The highest state of the latter series contains a 17% admixture of P-1(o) configurations, so one-photon excitation of-this state from the S-1(e) ground state is far from forbidden.