Brueckner-Hartree-Fock calculations using density-dependent effective interactions. Application to O<SUP>16</SUP>

The effects of allowing variations in the radial orbital wave functions, or major shell mixing, have been investigated within the framework of Brueckner-Hartree-Fock (BHF) theory for O<SUP>16</SUP>. The calculation is carried out in the matrix representation using harmonic-oscillator wave functions as a basis. Effective G matrix elements are calculated through the use of a density-dependent, two-body operator following a prescription of Bethe. Two possible parametrizations, the local-density approximation and an average-density approximation, are compared. Consideration of the rearrangement energy shows that it is an important contribution to the binding energy. The problem is formulated in a way which facilitates the application of BHF theory to deformed as well as spherical nuclei