Quadrupole Moment of the h11/2 Quasineutron Band in 129Ce

Mean lifetimes of the h11/2 quasineutron band in 129Ce were measured by using the Doppler shift attenuation method in connection with the reaction 116Sn (16O, 3n)129Ce at a bombarding energy of 73 MeV. The data indicate that transition quadrupole moment of 129Ce is smaller than that of 128Ce. This reduction in collectivity caused by the addition of an h11/2 neutron can be interpreted as due to triaxiality induced by γ driving effect.