Shell-model and Hartree-Fock calculations for even-mass O, Ne, and Mg nuclei

Shell-model and deformed Hartree-Fock plus BCS calculations are reported for even-even nuclei 18-30O, 18-36Ne, and 20-42Mg; shell-model calculations additionally included 38,40Ne and 44,46,48Mg. Ground-state binding energies and 2+1 quadrupole moments are calculated by both models. Shell-model calculations, aided by a new truncation method, include 2+1 excitation energies and magnetic moments. Hartree-Fock calculations with SkI6, RATP, Z*σ, and SkX Skyrme forces include ground-state deformations and rms radii; SkI6 gives the best overall agreement with experiment. The two models are compared with each other and with experiment. Two-neutron separation energies, evidence for a neutron halo or skin in heavy O isotopes, and deformation of Ne and Mg isotopes are discussed. Both models indicate disappearance of the shell gap at N = 28 (Mg), and the shell model does so additionally at N = 20 (Ne and Mg)

High-resolution study of the beta decay of Ti-41

An improved high-resolution study of the beta decay of Ti-41, produced in the Ca-40(He-3,2n) reaction at 40 MeV, has been performed at the Ion Guide Isotope Separator On-Line (IGISOL) facility. The beta-delayed radiation was detected by a low-energy charged-particle detector and a large Ge detector for gamma rays. The experimental beta-decay strength and its distribution, extracted from delayed-proton data, are compared with results of shell-model calculations in the sdfp space. The lowest J(pi) 3(+)/2, T = 3/2 state in (41) Sc, the isobaric analogue state of the Ti-41 ground state, is estimated to contain 10% isospin impurity. (C) 1997 Elsevier Science B.V

Beta decay of the M-T=-1 nucleus Zn-58 studied by selective laser ionization

Beta decay of Zn-58 has been studied for the first time. A new laser ion-source concept has been used to produce mass-separated sources for beta and gamma spectroscopy. The half-life of Zn-58 was determined to be 86(18) ms. Comparisons are made with previous data from charge-exchange reactions. Our Gamow-Teller strength to the 1(+) state at 1051 keV excitation in Cu-58 agrees well with the value extracted from a recent (He-3, t) study. Extensive shell-model calculations are presented