Level scheme of 65Ga

The level scheme of 65Ga has been studied up to an excitation energy of 7035.3 keV and spin-parity values of (27/2+). Gamma-ray singles, γγ-coincidences, angular distributions and Doppler shift attenuation have been measured in the reaction 63Cu(α, 2nγ) at 30 MeV. The spin and parity (Jπ) assignments for several states belonging to the previously known bands are confirmed. The mean life and the parity of the 2814.7 keV state, hitherto unknown, are reported. The Jπ for the 3733.2 keV state is proposed to be 15/2+ on the basis of angular distribution data and its decay characteristic to the lower-lying states. Experimental evidence is presented in favour of the 3733.2 keV state of being a band head for a rotation-like ΔΙ=2 positive-parity band with the excited members at 4547.5, 5643.5 and 7035.3 keV. The deduced B(E2) results indicate the presence of appreciable collectivity in the other positive-parity band built on the 9/2+, 2037.3 keV state. These bands in 65Ga are discussed and compared with similar bands in the neighbouring odd-A nucleus 67Ga