First observation of excited states in the Tz = 1/2 nucleus 85Mo

Excited states in the Tz=1/2 nucleus 85Mo have been observed for the first time with the reaction 58Ni(32S,αnγ) at 105 MeV. γ-ray transitions in this nucleus have been assigned unambiguously by combining the information from the GASP γ-ray array, the ISIS silicon ball, and the n-Ring neutron detector. Two band structures have been observed in this nucleus; they continue the smooth evolution of the known bands from the lighter N=43 isotones and have been tentatively assigned spins and parity on this basis. After reaching a maximum of collectivity at 83Zr, the trend with increasing mass is reversed, showing a smaller collectivity at 85Mo. The rotational behavior of the observed bands is discussed on the basis of the projected shell model calculations.