Spin, moments, and mean square nuclear charge radius of 77Sr

The neutron deficient 77Sr nucleus was studied by fast ion beam collinear laser spectroscopy with a detection scheme based on optical pumping, state selective neutralization, and atom counting. From the measured hyperfine splitting and isotope shift of the Sr II transition 5s 2S1/2→5p 2P3/2 the nuclear spin I=5/2, the nuclear moments μ=-0.348(4)μN, Qs=1.40(11) b, and the change in mean square charge radius δ left-angle r2 right-angle 88,77=0.248(12) fm2 were deduced. These ground-state properties indicate a large prolate deformation of ε2 congruent 0.4 and allow a comparison with calculations performed in the particle-plus-deformed-core model, assigning a [422]5/2 Nilsson configuration to the ground state of 77Sr