The nuclear spectra of ${}_{}{}^{54,56,58}{}_{}{}^{}\mathrm{Fe}$ and ${}_{}{}^{58,60,62}{}_{}{}^{}\mathrm{Ni}$ are obtained by mixing various bands. The bands for each nucleus are obtained by considering the prolate and oblate Hartree-Fock solutions. The third band is obtained by considering two-particle-two-hole excitations on whichever is the lower solution of the above two. The states with definite angular momenta are projected and the orthogonalization is carried out to obtain the nuclear spectra. The Yukawa-Rosenfeld interaction (YR) and the Kuo-Brown interaction modified by McGrory et al. (KM) are used as the two-body interactions. The single particle energies are varied for each mucleus to give a good fit. A comparison between the interactions shows that the KM interaction for the Fe isotopes and the YR interaction for the Ni isotopes give better results. In general, the agreement with the experimental spectra is very good. However, the second $2^{+}$ state in ${}_{}{}^{56,58}{}_{}{}^{}\mathrm{Fe}$ and ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$ cannot be explained by this model which considers only $K=0\mathrm{}$ bands. The high spin states have also been obtained. The effects of the band mixing on the nuclear spectra are discussed in detail for each nucleus.

NUCLEAR STRUCTURE ${}_{}{}^{54,56,58}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{58,60,62}{}_{}{}^{}\mathrm{Ni}$ calculated energy levels. Projected Hartree-Fock method, band mixing.

• Received 21 August 1974

DOI:https://doi.org/10.1103/PhysRevC.10.2568