PROJECTED QUASI-PARTICLE CALCULATIONS OF SN-119, SN-121, AND SN-123 USING REALISTIC INTERACTIONS

We have performed quasi-particle calculations for the tin isotopes Sn- 119, Sn-121 and Sn-123, using realistic effective interactions derived from the Paris and Bonn-A NN potential. A number-projected one- and t hree-quasi-particle formalism in the (g(7/2), d(5/2), d(3/2), s(1/2), h(11/2)) model space is employed. We have used a folded-diagram method to derive the corresponding model-space effective interaction, starti ng from the G-matrix elements derived from the above NN potentials. Th e G-matrix Pauli-exclusion operator Q(2), specified by the shell-model orbitals (n(1), n(2), n(3)) = (11, 21, 36), has been treated accurate ly. An almost pure (h(11/2))(3) three-quasiparticle structure for the high spin states from J = 17/2(-) to 27/2(-) of the above nuclei has b een observed. With practically no parameter adjustment our calculated energies are in very good agreement with available experimental data.