Abstrakt
The isoscalar giant monopole resonance (GMR) in spherical nuclei Sn100-132, Sm-144 and Pb-208 is investigated within the Skyrme random-phase approximation for a variety of Skyrme forces and different pairing options. The calculated GMR strength functions are directly compared to the available experimental distributions.
It is shown that, in accordance with the results of other groups, the description of GMR in Sn and heavier Sm/Pb nuclei needs different values of nuclear incompressibilty, K approximate to 200 or 230 MeV, respectively. Thus, none of the Skyrme forces used can simultaneously describe GMR in these nuclei.
The GMR peak energy in open-shell Sn-120 is found to depend on the isoscalar effective mass, which might be partly used to solve the above problem. Some important aspects of the problem, such as discrepancies of available experimental data and proper treatment of the volume and surface compression in finite nuclei, are briefly discussed.