Projected quasi-particle calculations of 119Sn, 121Sn, and 123Sn using realistic interactions

We have performed quasi-particle calculations for the tin isotopes ¹¹⁹Sn, ¹²¹Sn and ¹²³Sn, using realistic effective interactions derived from the Paris and Bonn-A NN potentials. A number-projected one- and three-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, starting from the G-matrix elements derived from the above NN potentials. The G-matrix Pauli-exclusion operator Q₂, specified by the shell-model orbitals ( n₁, n₂, n₃) = (11, 21, 36), has been treated accurately. 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 been observed. With practically no parameter adjustment, our calculated energies are in very good agreement with available experimental data.