DISCOVERY OF STRONGLY ENHANCED LOW ENERGY ALPHA DECAY OF A LONG-LIVED ISOMERIC STATE OBTAINED IN ¹⁶O + ¹⁹⁷Au REACTION AT 80 MeV, PROBABLY TO SUPERDEFORMED BAND

The reaction ¹⁶O + ¹⁹⁷Au has been studied at a bombarding energy of 80 MeV. A group of 5.20 MeV α particles with a half-life of about 90 m has been found in coincidence with characteristic X-rays of At and with γ-rays. The γ-ray energies fit predicted energies for superdeformed band. The data are interpreted as due to formation of a long-lived isomeric state which decays by low energy α-particles to SD band. The calculated probability for decay via a barrier of a superdeformed nucleus was found to be consistent with the experimental results.