Different seniority states of 119-126Sn isotopes: Shell-model description

Abstract

In the present work, available experimental data up to high-spin states of 119-126Sn isotopes with different seniority (v), including v = 4, 5, 6, and 7, are interpreted with the shell model, by performing shell-model calculations in the 50-82 valence shell composed of 1g7/2, 2d5/2, 1h11/2, 3s1/2, and 2d3/2 orbitals. The results are compared with the available experimental data. These states are described in terms of broken neutron pairs occupying the h11/2 orbital. Possible configurations of seniority isomers in these nuclei are discussed. The breaking of three neutron pairs is responsible for generating high-spin states. The isomeric states 5-, 7-, 10+, and 15- of even Sn isotopes, and isomeric states 19/2+, 23/2+, 27/2-, and 35/2+ of odd Sn isotopes, are described in terms of different seniority. For even Sn isotopes, the isomeric states 5-, 7-, and 10+ are due to seniority v = 2; the isomeric state 15- is due to seniority v = 4, and, in the case of odd Sn isotopes, the isomeric states 19/2+, 23/2+, and 27/2- are due to seniority v = 3, and the isomeric state 35/2+ in 123Sn is due to seniority v = 5. These are maximally aligned spins, which involve successive pair breakings in the v(h11/2) orbital.