Monopole vibrations in asymmetric nuclei: A Fermi liquid approach Original Research Article

Isoscalar and isovector monopole responses of a neutron–proton asymmetric finite system are studied within a semiclassical approach based on the Vlasov kinetic equation. Both the isoscalar and the isovector vibration are considered simultaneously using a self-consistency condition with the phenomenological surface pressure. We focus on the influence of the neutron excess on the strength distribution of the monopole vibrations in nuclei near the stable line. It is found that the effects of the neutron–proton asymmetry on the monopole strength function are essentially due to the Landau (one-body) damping. The isoscalar monopole strength is concentrated on one giant peak. The neutron–proton asymmetry decreases the collectivity of isovector monopole resonance. This decrease is due to the strengthening of the Landau damping. Surface effects are essentially implicated in the isovector monopole resonance.