Shell corrections to a liquid-drop description of nuclear masses and radii

It is shown that a consistent treatment of nuclear bulk and surface effects leads to an improved version of the liquid-drop mass formula with modified symmetry and Coulomb terms. If in addition shell effects are modelled through the counting of the number of valence nucleons, a very simple mass formula is obtained with an rms deviation from the 2003 database of atomic masses of about 800keV. As an application, the volume and surface symmetry energy for A \( \rightarrow\) ∞ are determined. A similar description of nuclear radii is suggested with specific reference to the neutron skin.