It is shown within the Hartree-Fock method with the Skyrme force that the quadrupole-quadrupole neutron-proton interaction gives the leading term in the nuclear deformation energy. The quadrupole-quadrupole coupling constants are derived and shown to agree with those obtained within the simple harmonic-oscillator model.

• Received 8 March 1988

DOI:https://doi.org/10.1103/PhysRevLett.60.2254