Improved Empirical Hamiltonians for Neutron-rich Nuclei in 132Sn region

Abstract

Using recent experimental information for 132Sn region, an empirical Hamiltonian is obtained by some modifications of a Hamiltonian (CW5082) originally derived from the 208Pb region. Shell model calculations with the new Hamiltonian shows remarkable improvement in the predictive power when compared with the available experimental results. It overcomes many limitations of the CW5082 Hamiltonian in this region, specially for N>=84 isotones. The calculated level spectra and B(E2) values with the new Hamiltonian, also compare well with the available results calculated with the CD-Bonn and SKX Hamiltonians, reflecting consistency in the wave function structure at least in the low-lying regions. Interesting behaviour of effective charges is revealed in this region. It is shown that a drastic reduction of proton effective charge is necessary for obtaining B(E2) values for the N=84 isotones. Neutron effective charge is found to be in the range (0.62 - 0.72)e. We predict the spectroscopic properties of 135,136Sn not yet known experimentally. Further improvement of the modified Hamiltonian is also initiated.