Dominant ( g 9 / 2 ) 2 neutron configuration in the 4 1 + state of Zn 68 based on new g factor measurements

The g factor of the 4 + state in 68 Zn has been remeasured with improved energy resolution of the detectors used. The value obtained is consistent with the previous result of a negative g factor thus confirming the dominant 0g9/2 neutron nature of the 4 + state. In addition, the accuracy of the g factors of the 2 + , 2 + and 3 − states has been improved and their lifetimes were well reproduced. New large-scale shell model calculations based on a 56 Ni core and an 0f 5/2 1pg 9/2 model space yield a theoretical value, g(4 + ) = +0.008. Although the calculated value is small, it cannot fully explain the experimental value, g(4 + ) = 0.37(17). The magnitude of the deduced B(E2) of the 4 + and 2 + transition is, however, rather well described. These results demonstrate again the importance of g factor measurements for nuclear structure determinations due to their specific sensitivity to detailed proton and neutron components in the nuclear wave functions.