Monopole-optimized effective interaction for tin isotopes

We present a systematic configuration-interaction shell-model calculation on the structure of light tin isotopes with a global optimized effective interaction. The starting point of the calculation is the realistic CD-Bonn nucleon-nucleon potential. The unknown single-particle energies of the 1d(3/2), 2s(1/2), and 0h(11/2) orbitals and the T = 1 monopole interactions are determined by fitting to the binding energies of 157 low-lying yrast states in Sn102-132. We apply the Hamiltonian to analyze the origin of the spin inversion between Sn-101 and Sn-103 that was observed recently and to explore the possible contribution from interaction terms beyond the normal pairing.