Nuclear Energy Levels of ${\mathrm{V}}^{51}$, ${\mathrm{Mn}}^{53}$, and ${\mathrm{Co}}^{55}$ by the Quasiparticle Method

The modified Tamm-Dancoff approximation has been applied to the calculation of the nuclear energy levels of ${\mathrm{V}}^{51}$, ${\mathrm{Mn}}^{53}$, and ${\mathrm{Co}}^{55}$. The shell-model reaction matrix elements of Kuo and Brown, calculated with the Hamada-Johnston nucleon-nucleon potential and renormalized for core polarization, are used with the aim of ascertaining the accuracy of these matrix elements. The effects of the extra term in the BCS equations and of the ground-state correlation are studied. Only a qualitative agreement between theoretical and experimental spectra is found for all three nuclei investigated.