High spin rotational bands in As-70 nucleus

Structures of the high spill states in the odd-odd nucleus As-70 have been investigated following two heavy-ion fusion evaporation reactions V-51(Si-2 8, 2 alpha n) and Ti-46(Si-28, 3pn). Seventeen new transitions have been fo und and placed in the le-vel scheme of As-70. The onset of collectivity is observed at high spill with the discovery of three rotational bands, simila r to As-72. The kinematic moments of inertia of these bands follow the gene ral systematics of mass 70 region. The pi [440]1/2(+) x nu [431]3/2(+) and pi [301]3/2(-) x [431]3/2(+) configurations are proposed for +ve and -ve pa rity bands, respectively. The finding of quite different signature splittin g for +ve parity bands in As-70 and As-72 is interpreted as due to differen t shapes of these nuclei from the Total Routhian Surface (TRS) calculations .