MISSING 19/2+ STATES IN PR-141 AND PM-143

A simple weak coupling model previously applied to the analysis of the yrast spectrum of Nd143 is extended to yrast spectra of odd-A N=82 and 83 isotopes of Z=58"61 nuclei. The model generally provides a good description of these spectra; however, yrast 19/2+ states expected to arise in Pr141 and Pm143 from the coupling of g7/2 holes to the 61+ states of the even-even cores are not observed experimentally. The absence of these states can be explained using a simple microscopic argument. © 1990 The American Physical Society.