THE CONGRUENCE ENERGY - A CONTRIBUTION TO NUCLEAR-MASSES, DEFORMATIONENERGIES AND FISSION-BARRIERS

The difference between measured binding energies and those calculated using a shell- and pairing-corrected Thomas-Fermi model can be describ ed approximately by C(I) = - 10 exp(- 4.2 / I /) MeV, where I = (N - Z )/A. Our interpretation of this extra binding is in terms of the granu larity of quantal nucleonic density distributions, which leads to a st ronger interaction for a neutron and proton with congruent nodal struc tures of their wave functions. The predicted doubling of this congruen ce energy in fission is supported by an analysis of measured fission b arriers and by a study of wave functions in a dividing Hill-Wheeler bo x potential. A semi-empirical formula for the shape-dependent congruen ce energy is described.