Shape coexistence in Hg, Tl and Pb nuclei beyond the 82<N<126 mid-shell

Abstract

In this thesis coexisting structures in the neutron-deficient 174, 176, 177Hg, 183TI and 182, 184Pb nuclei have been studied at the Accelerator Laboratory of the University of Jyväskylä. To probe these nuclei in the close vicinity of the proton drip-line the Recoil-Decay-Tagging (RDT) technique based on the use of a germanium detector array in conjunction with the gas-filled recoil separator RITU has been utilised. The excited states have been observed for the first time in 174, 177Hg and 182, 184Pb nuclei. The energies of newly observed levels in 176Hg and the band-head of the yrast πi13/2 band in 183Tl have been determined. The experimental results are compared both to the level-energy systematics of the heavier isotopes and theoretical predictions. The new results are in accordance with the scheme of the intruding prolate-deformed structures minimising their energies near the N=104 neutron mid-shell in Hg and Pb nuclei.