In this work we have reported on the development and detailed testing of a fully self-consistent Skyrme-QRPA framework that employs the canonical HFB basis. The method can be used to calculate strength distributions in any spin-isospin channel and in any spherical even-even nucleus. A good calculation requires a large single-quasiparticle space. Our results show that our space is large enough in nuclei as heavy as the Sn isotopes.
We are currently investigating the predictions of a range of Skyrme functionals across the Ca, Ni, and Sn isotope chains. The initial results presented here point to increases in low-lying strength at the neutron drip line, particularly in the isoscalar-dipole channel. In a forthcoming paper [76] we will report on the robustness of these effects, on the physics underlying them, on their variation with atomic mass and number, and on their implications for the future of Skyrme functionals.
We gratefully acknowledge useful discussions with Shalom Shlomo, Nils Paar, Dario Vretenar, and the Japanese members of the US-Japan cooperative project on ``Mean-Field Approach to Collective Excitations in Unstable Medium-Mass and Heavy Nuclei". MB is grateful for the warm hospitality at the Physics Division at ORNL and the Theory Division at GSI Darmstadt, where most of his contribution to this work was made. This work was supported in part by the U.S. Department of Energy under Contracts Nos. DE-FG02-97ER41019 (University of North Carolina at Chapel Hill), DE-FG02-96ER40963 (University of Tennessee), DE-AC05-00OR22725 with UT-Battelle, LLC (Oak Ridge National Laboratory), DE-FG05-87ER40361 (Joint Institute for Heavy Ion Research), and W-31-109-ENG-38 (Argonne National Laboratory); by the National Science Foundation Contract No. 0124053 (U.S.-Japan Cooperative Science Award); by the Polish Committee for Scientific Research (KBN); and by the Foundation for Polish Science (FNP). We used the parallel computers of The Center for Computational Sciences at Oak Ridge National Laboratory and Information Technology Services at the University of North Carolina at Chapel Hill.