Proceedings of the International School of Physics "Enrico Fermi.", Volume 36

a-clusters amplitude angular momentum antisymmetrized approximation calculations closed shell closed-shell coefficients commutation configurations consider corresponding coupling defined deformed denotes density matrix diagonal diagrams effective field eigenfunctions eigenstates eigenvalue equation example excitation expansion experimental expression external field Fermi level formalism given gives graphs Green's function ground-state Hamiltonian Hartree-Fock hole integral isospin isotopes matrix elements method multipole neutron Nucl nuclear nuclei nucleons number of particles obtain occupation numbers one-body operator orbit orthogonal P₁ pairing force parameters parity particle-hole pair perturbation Phys potential properties protons quadrupole quantity quantum number quasi-particle Rendiconti S.I.F. representation residual interaction rotational scalar Sect secular problem self-consistent shell-model simple Slater determinants solution space spherical spin sum rules symmetry t₁ tensor theory transformation transition rates two-body unperturbed vacuum values vector wave functions zero