Shell-independent systematics S n (isotonic) and S p (isotopic)

Abstract

Graphs are presented of recent values for the separation energy of a given neutron versus mass number, S n (isotonic), and for a given proton versus neutron number, S p (isotopic). The graphs confirm the fact, pointed out by Yamada and Matumoto in 1961, that the separation energy of the n th proton increases monotonically (except for oddeven effects) as the neutron number is increased, showing little, if any, discontinuity at magic neutron numbers. An analogous statement can be made for the separation energy of the n th neutron as the proton number is increased. Extrapolation by means of the graphs should, therefore, be particularly reliable since it is essentially magic-number independent. Data available in the summer of 1967 have been considered.