R PALIT, H C JAIN, P K JOSHI and J A SHEIKH

Tata Institute of Fundamental Research, Mumbai 400 005, India

Abstract.

Lifetimes of high spin states up to I^p = 22⁺ in the yrast positive parity bands have been measured to investigate the shape evolution with increasing spin in ^72,74Se. The Q_t values derived from these measurements indicate that prolate shape stabilizes for ⁷²Se, while a triaxial shape develops for ⁷⁴Se at higher spins. Comparison of the observed trend in Q_t with spin for ^72,74Se with that of the corresponding kryptones isotones emphasizes the stability provided by N = 38 prolate shell gap even at high rotational frequency.

Keywords:  Alignment; projected shell model; lifetime; shell gap.

Pacs Nos.  21.10.Tg; 21.60.Cs; 27.50.+e