The SD pair condensate description of low-energy nuclear states is investigated in detail for ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ and ${}_{}{}^{58}{}_{}{}^{}\mathrm{Fe}$, using a shell model space of protons in the 1${\mathit{f}}_{7/2}$ orbit, and neutrons in the 2${\mathit{p}}_{3/2}$, 1${\mathit{f}}_{5/2}$, and 2${\mathit{p}}_{1/2}$ orbits. A direct method is employed in that eigenstates corresponding to low-energy levels are themselves analyzed to identify which are indeed well described in this manner. For those where such a description is appropriate, the emergence of dynamical symmetries in the mapped boson system, and in particular the identification of ‘‘mixed-symmetry’’ states, is also investigated. Results are satisfactory for the low-spin levels, and indicate an approximate U(6)⊃SO(6) dynamical symmetry.

• Received 24 July 1989

DOI:https://doi.org/10.1103/PhysRevC.41.2340