Relation between the Binding Energy and Scattering Phase Shift

It is “well known” in the potential scattering in quantum mechanics that it is, in principle, impossible to obtain information about the binding energy from the scattering phase shift, and vice versa. This is illustrated in a simple way for the case of a nonlocal separable potential. The implications of the “relation” between the deuteron binding energy and the low-energy proton-neutron scattering parameters in the S3 state are discussed.