Long standing problem of 210Bi and the realistic neutron-proton effective interaction

TL;DR

This paper investigates the nucleus 210Bi using shell model calculations with realistic interactions, successfully reproducing experimental energy levels and explaining the ground state inversion through core-polarization effects.

Contribution

It demonstrates the importance of core-polarization effects in realistic shell model interactions for odd-odd nuclei, providing improved understanding of 210Bi's structure.

Findings

Accurately reproduces experimental energies of 210Bi

Explains the 1- ground state via core-polarization effects

Highlights similarity between neutron-proton multiplets in different regions

Abstract

The odd-odd nucleus 210Bi is studied within the framework of the shell model using effective two-body matrix elements derived from the CD-Bonn nucleon-nucleon potential. The experimental energies of the proton-neutron multiplet ph9/2 ng9/2 are remarkably well reproduced by the theory, which accounts for the 1- state being the ground state instead of the 0- predicted by the Nordheim strong coupling rule. It is shown that the core-polarization effects are crucial to produce this inversion. The similarity between neutron-proton multiplets in the 132Sn and 208Pb regions is discussed in connection with the effective interaction.