Abstract
The configuration interaction (CI) optical potential for electron-molecule scattering is rederived. This optical potential is conventionally defined by a Feshbach projection of the configuration interaction matrix onto the open channels. Here the author presents a slightly different derivation. The Schwinger multichannel formalism is then shown to be equivalent to the CI optical potential approach. The Schwinger multichannel formalism hence suffers from the same sensitivity on the target ground state as does the CI optical potential.