Valency effects in compound nucleus level spacings

Abstract

It is shown that nuclides whose proton or neutron numbers lie within three units of a magic number have a level density parameter that is very strongly correlated with the Myers-Swiatecki shell correction to the mass formula. Using this correlation 93 level densities are calculated from only two adjustable constants in a semi-empirical fashion. It is shown that since weaker correlations exist in five regions of the periodic table intermediate and heavy nuclides which lie between the strong correlation ranges also give satisfactory fits thus making a twelve-parameter fit overall.