Repulsion of nuclear levels

Abstract

The size distribution of level spacings in the region of compound nucleus excitation energies of the order of the neutron binding energy is considered. By analyzing available data derived by neutron spectroscopy, it is shown that the actual size distribution of level spacings qualitatively differs from random distribution. The relative number of near-lying levels is considerably smaller than for a random distribution. The conclusion is drawn that nuclear levels “repel” each other with a distribution approaching equidistance. This conclusion is based on experimental data relating mainly to odd-mass target nuclei. Assuming naturally that only equal spin levels interact, the observed “repulsion” may prove to be less pronounced owing to overlapping of the two sets of levels.