Experimental and theoretical characterization of effective interactions near 132Sn

Experimental investigations have been undertaken to study the multiplet structure in six nuclei near 132Sn: 132,130Sb, 131,129,127Sb, and 132Te. Experiments were performed using ion beams of mass-separated fission products produced by the TRISTAN mass separator at Brookhaven National Laboratory. Extensive four-detector gamma-gamma coincidences, gamma-multiscaling and conversion-electron data have been collected. The previously unobserved 5+ member of the πg7/2 circle-times vd3/2 multiplet has now been observed in 132,130Sb. These studies have also found that the 130Sb ground state is the 8- isomer with the 4+ metastable isomer at an energy of 5.1 keV. Studies on 131,129,127Sb have located members of multiplets and complete the systematics from 123-131Sb. A 17.1 min. β- decaying isomer was observed in 129Sb and defines a 19/2- level at 1851.29 keV. Isomerism has also been studied in 132,130,130,129Sb and in 132Te. Ultralarge shell model calculations were performed using the VLADIMIR shell model code on the Cray/CDC 7600 supercomputer system at Lawrence Livermore National Laboratory. Results show that realistic potentials work well on nuclei near 132Sn but show problems with 129,130Sn and 131Sb which can not be accounted for by core-polarization corrections