STRUCTURE OF HIGH-SPIN YRAST STATES IN PB-205 AND PB-206

The properties of high-spin states in Pb-205 and Pb-206 have been inve stigated using the Hg-204(Be-9, alpha4n)Pb-205 Hg-204(Be-9, alpha3n)Pb -206 reactions at a bombarding energy of 62 MeV. Decay properties for states up to an excitation energy of 6866 keV and spin of (37/2+) have been deduced for Pb-205, and up to an excitation energy of 8705 keV a nd spin of (21+) for Pb-206. The level schemes are compared with predi ctions of multi-particle shell-model calculations. The observation tha t the yrast 33/2+ isomer in Pb-205 is essentially bypassed is explaine d as a consequence of the absence of related configurations of higher spin near the yrast line.