FINITE-SIZE EFFECTS IN THE GAP EQUATION FOR PARIS INTERACTION

The pairing problem in nuclei is approached starting from a realistic nucleon-nucleon interaction and solving the full gap equation in a com plete basis. To this purpose the original bare nucleon-nucleon interac tion, a separable form of the Paris potential, in the S-1(0) channel i s first renormalized into a large spherical Woods-Saxon basis which in cludes single-particle levels up to 100 MeV. The corresponding matrix elements in the Woods-Saxon basis are then used to solve exactly the g ap equation. Proton and neutron gaps are computed for Cr and Fe isotop es. Finite-size effects are evidenced.