Macroscopic model of the nucleus

The mass formula is derived from a continuous medium model with variable densities. The parameters contained in the formula are determined by fitting the experimental atomic masses, root-mean-square charge radii, and the Coulomb energy differences between isobaric analog states. With our formula and the shell corrections of Moeller and Nix, the nuclear masses for 1333 nuclides from A = 20 to 259 are calculated. The root-mean-square deviation of the fitting is 0.803 MeV. The calculated charge densities, root-mean-square charge radii, and Coulomb-energy differences between isobaric analog states are also in good agreement with the empirical data