Eigenchannel calculation for a soluble model

We examine the accuracy of the eigenchannel method for treating nuclear reactions by a comparison with the exact solution of a problem of two coupled channels. No crucial deviations between the exact and the eigenchannel cross sections are observed. We also discuss the questions connected with the non-orthogonality of the sets of radial states used in the eigenchannel treatment, and show how to minimize the resulting errors. Our conclusion is that, in principle, the eigenchannel method is capable of producing the correct shape of nuclear cross sections, without introducing spurious wiggles.