A New Regularity in the List of Existing Nuclei

Abstract

In the absence of a theory of nuclear constitution, a search for regularities in the list of existing nuclear types is of value. Aston's data form a fairly complete list up to atomic number 61. Previous investigations disclosed evidence of several types of regularity. A new type has been observed in which most of the known nuclei in the range studied fall into three clusters, each characterized by a two dimensional symmetry. More specifically, when the nuclei are plotted as points whose ordinates and abscissas indicate the number of protons and electrons respectively in their constition, there exists for each cluster a center ($P,E$) such that if there is a nuclear type ($P-X,E-Y$) there is, in general, also a symmetrical type ($P+X,E+Y$). A consideration of the relatively few departures from this rule within the clusters leads to a list of predicted isotopes as yet undiscovered. A possible physical interpretation of the new type of regularity is tentatively suggested. The considerations advanced apparently do not apply to a number of points scattered through the regions between the clusters.