Neutron and Proton Binding Energies in the Region of Lead,

The maxima in alpha particle decay energies for mass numbers 2l0-2l5 recently emphasized by Perlman, Ghiorso, and Seaborg can be looked at in terms of neutron and proton binding energies and, when thus interpreted, reveal rather sharp discontinuities in these bindings at proton number 82 and neutron number 126. The numbers 82 and 126 are two of the magic numbers connected with marked nuclear stability on which attention has been focused by M. G. Mayer. If one considers these magic numbers as numbers for which neutron or proton shells are closed one would expect unusually high binding energies for the 82nd, 81st, etc., proton and for the 126th, l25th, etc., neutron and unusually small bindings for protons with number slightly greater than 82 and neutrons with number slightly greater than 126. As the new shells fill up, the binding energies should gradually return to normal. jg p.2