Underlying structure of continuum response functions in random phase approximation

Abstract It is shown that continuum-RPA results can be understood in terms of energy-dependent, complex RPA states. These states have finite widths which are direct escape widths. Calculations have been performed for a simple model of monopole resonance in 40 Ca, and the results are compared with those obtained by continuum-RPA and time-dependent Hartree-Fock methods.