A generalized approximation to seniority shell model, based on the number conserving quasiparticle theory, is presented which includes the cases where both neutrons and protons are present in the valence shells. The numerical calculations are carried out for even Zr isotopes. The results obtained compare well with the corresponding exact shell model results, demonstrating thereby the validity of the present approximation for this nuclear region.

NUCLEAR STRUCTURE Shell Model, Seniority Shell Model, Broken-Pair Approximation (BPA), Generalized BPA, Zr-isotopes

• Received 30 November 1978

DOI:https://doi.org/10.1103/PhysRevC.20.381