The validity of the broken-pair approximation as an approximation to the seniority shell model is investigated. The results of the broken-pair approximation and the seniority shell model, obtained by employing identical input information (single-particle levels and their energies, effective two-body matrix elements, ${}_{}{}^{88}{}_{}{}^{}\mathrm{Sr}$ inert core) for $N=50\mathrm{}$, even-$A$ nuclei are compared. A close agreement obtained between the calculated broken-pair approximation and the seniority shell model energies for ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$, ${}_{}{}^{94}{}_{}{}^{}\mathrm{Ru}$, and ${}_{}{}^{96}{}_{}{}^{}\mathrm{Pd}$ nuclei and large (95-100%) overlaps between the broken-pair approximation and the senority shell model wave functions for ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$, demonstrates the validity of the broken-pair approximation in this region and in general its usefulness as a good approximation to the seniority shell model.

NUCLEAR STRUCTURE Shell model, seniority shell model, broken-pair approximation, quasiparticle Tamm-Dancoff (QTD), projected QTD; ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, ${}_{}{}^{92}{}_{}{}^{}\mathrm{Mo}$, ${}_{}{}^{94}{}_{}{}^{}\mathrm{Ru}$, ${}_{}{}^{96}{}_{}{}^{}\mathrm{Pd}$.

• Received 15 March 1977

DOI:https://doi.org/10.1103/PhysRevC.16.2455