Trapping effect and high-lying single-particle modes

The phenomenon of trapping of states is studied in the case of high-lying states with large angular momentum in the odd-A nucleus ²⁰⁹Pb. The interaction of the single-particle mode with more complex states is calculated in the framework of the quasiparticle-phonon model while the coupling to the continuum is included by means of the projection operator method. The results obtained show a reduction of the spreading of the single-particle strength under the influence of the coupling to the continuum: the strength is concentrated on a few collective states while the remaining states are decoupled from the continuum (trapped). The results are compared with the case where continuum coupling is switched off. The influence of the continuum on the nuclear structure should be visible in nucleon transfer reactions.