A Thomas-Fermi model of nuclei. II. Fission barriers and charge distributions

The Thomas-Fermi model of average nuclear properties described in Part I (Myers and Swiatecki, Ann. Phys. (N.Y.)204, 1990, 401–431) is simplified further and then applied to the calculation of fission barriers and charge distributions. An extensive comparison with experimental data reveals a small but clear-cut barriers vs size discrepancy: if the radius constant r0 is chosen to be 1.13 fm so as to reproduce measured nuclear sizes, the calculated fission barriers are too high. The suggestion is made that an extension of the Thomas-Fermi method is called for in order to describe the presence in nuclei of the “quantal halo”, i.e., of the classically forbidden region around the nuclear surface where matter exists at negative kinetic energy.