Pygmy dipole resonance in stable Ca isotopes Original Research Article

The properties of the low-lying electric dipole strength in the stable 40Ca,44Ca and 48Ca isotopes have been calculated within the Extended Theory of Finite Fermi Systems (ETFFS). This approach is based on the random phase approximation (RPA) and includes the single-particle continuum as well as the coupling to low-lying collective states which are considered in a consistent microscopic way. For 44Ca we also include pairing correlations. A good agreement with the existing experimental data for the gross properties of the low-lying strength has been obtained. We conclude that for the detailed understanding of the low-lying dipole strength an approach like the present one is absolutely necessary.