Resonance states using the optical potential model. Study of Feshbach resonances and broad shape resonances

A previous paper presented the study of resonance states by adding a trial imaginary potential to the Hermitian Hamiltonian and reported results for the Hazi Taylor potential. This study shows that this model can be applied successfully to Feshbach resonances and to broad shape resonances for a spherical van der Waals potential. In the case of shape resonances a nonstationary test takes advantage of the strong dependence of the resonance eigenvalue on the shape of the wall through which the wave function tunnels.