Access provided by 44.224.250.200 on 05/10/21. For personal use only.1. choice of H l' the dominant central field;2. calculation of the one-particle eigenstates of HI and the selection, from this set, of the orbits of the model; 3. construction, for a given number of nucleons and the chosen model orbits, of the multinucleon eigenstates of HI; 4. specification of a residual two-body interaction of H 12; and 5. evaluation of the matrix elements of H 1 2 between the multinucleon eigenstates of HI and calculation of the eigenvalues and eigenvectors of this matrix.Many calculations assume that HI is a sum of a spherical harmonic oscillator potential, a spin-orbit (I• s) interaction, and a term proportional to 12. The single-particle eigenstates p(nlj) of a typical such interaction are shown in Figure 1 where the labels (n, i,j) specify the principal radial quantum number, the orbital angular momentum, and the total angular momentum. The simplest shell-model calculations, similar to those that first established the validity of the basic approximation (Mayer 1949), assume wave functions in which the nucleons fill the lowest available single particle orbits, where this availability is determined by the Pauli principle.Thus from Figure 1, the ground-state wave function of 170 would consist of the configuration (OSI/2)4, (Op3/2)8, (Opl/2)4, (Ods/2) 1 . The completely filled ("closed") shells are assumed to form an inert core with total angular