Equations-of-motion method and pairing correlations in odd-A nuclei

An equations-of-motion method is presented for treating pairing correlations in odd-A nuclei. This method is the natural extension of a previous study of the pairing problem in doubly even nuclei, which provides the input data for the present work. It is shown that the spurious states arising from the use of an overcomplete set of basis vectors can be removed through a procedure analogous to that developed for the doubly even case. The energies, spectroscopic factors, and occupation probabilities of seniority-one states in the Ni isotopes are calculated in the first-order theory. By comparison with exact results, the accuracy of the method is seen to be very good.