Adiabatic hyperspherical potential curves are calculated for very highly excited states of ${\mathrm{H}}^{\mathrm{-}}$ converging to H(n≤12). These potential curves reveal surprisingly weak channel interactions, manifested as extremely diabatic multiple curve crossings. We demonstrate that only resonances associated with the lowest ‘‘+’’ diabatic channel within each n manifold are observed in the recent experiments at Los Alamos (Harris et al.). A simple Rydberg-dipole formula gives the positions of all dominant resonances, permitting extrapolation to arbitrarily high quantum numbers.

• Received 13 March 1990

DOI:https://doi.org/10.1103/PhysRevLett.65.313