The soft Giant Monopole Resonance as a probe of the spin-orbit splitting

Abstract

The isoscalar monopole response is studied in doubly magic Pb-208 , Sn-100,Sn- 132 nuclei using the Skyrme HF+RPA model. A low-energy strength is predicted and corresponds to almost pure single-particle excitations. These pure single-particle excitations allow to analyse the splitting of the corresponding spin-orbit partners. A good agreement with the spin-orbit splitting data is found in the case of Pb-208 . The experimental width of the giant monopole resonance may hinder the measurement of the soft monopole mode.