2006/03/21 by G. Tertychny, V. Tselyaev, S. P. Kamerdzhiev +9 · 2 citations
Physics and Astronomy · #Advanced Chemical Physics Studies #Nuclear physics research studies #Rare-earth and actinide compounds #nucl-th
paper · pdf · doi:10.1016/j.physletb.2007.01.069
published as Physics Letters B647 (2007) 104 · 6 figures
arxiv created 2006/03/21 · openalex publication_date 2007/02/21 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/29
The properties of the pygmy (PDR) and giant dipole resonance (GDR)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 collectives states which are considered in a consistent microscopic way. For 44Ca we also include pairing correlations. We obtain good agreement with the experimental data for the gross properties of both resonances. It is demonstrated that the recently measured A-dependence of the strength of the PDR below 10 MeV is well understood in our model:due to the phonon coupling some of the strength in 48Ca is simply shifted beyond 10 MeV. The predicted fragmentation of the PDR can be investigated in (e,e') and (γ,γ') experiments. Whereas the isovector dipole strength of the PDR is small in all Ca isotopes, we find in this region surprisingly strong isoscalar dipole states, in agreement with an (α,α'γ) experiment. We conclude that for the detailed understanding of the structure of excited nuclei e.g. the PDR and GDR an approach like the present one is absolutely necessary.