Resonances in Multichannel Scattering

The formalism of Feshbach as used by O'Malley and Geltman for finding resonances in elastic electron-hydrogen scattering is extended to more than one channel. A result of Feshbach's is rederived. It is found that resonances occur in all open channels at the same energy and with the same width. Infinities of "resonances" are found below the higher $N$ levels in electron-hydrogen scattering, and recurrence relations determining the relative positions of the higher resonances are found.