Changes in nuclear shell structure studied by their nuclear moments.

This project aims to investigate the structure of exotic nuclei, in particular in regions where a change in the shell structure is expected, by comparing measured nuclear g-factors and quadrupole moments to nuclear model calculations. For this, an evaluation of all available static quadrupole moments is recommended. Quadrupole moments are extracted from measured quadrupole frequencies if the electric field gradient (EFG) is known. In the last years, reliable calculations of EFGs have become possible for solids using ab-initio models [Schwarz 02]. A relative frequency measurement with respect to a reference isotope also yields a quadrupole moment, provided a reference quadrupole moment is known [Pyykkö 01]. Often, quadrupole moments in literature are based on different references. Using the adopted reference values from [Pyykkö 01], we can re-evaluate all available data for chains of isotopes, in order to obtain quadrupole moments relative to one single reference isotope. A systematic comparison to nuclear model calculations will allow to test their predictive power in regions far from stability or to fix effective charges. Deviations from the model calculations can point to changes in the shell structure and the need for modifications of the effective interactions. Apart from making the evaluation and comparison to theory, we will continue our efforts in using spin-oriented radioactive beams for nuclear moments measurements. [Pyykkö 01] P. Pyykkö, Molecular Physics vol. 99, 1617 (2001). [Schwarz 02] Computer Physics Communications 147, 71-76 (2002)

Keywords:Nuclear structure, Nuclear moments, G-factor, Quadrupole moment, Shell evolution

Disciplines:Nuclear physics