Large odd-even radius staggering in the very light platinum isotopes from laser spectroscopy

Laser spectroscopy measurements have been carried out on very-neutron-deficient platinum isotopes with the COMPLIS experimental setup. Using the 5d96s3D3→5d96p3P2 optical transition, hyperfine spectra of 182,181,180,179,178Pt and 183Ptm were recorded for the first time. The variation of the mean square charge radius between these nuclei, the magnetic moments of the odd isotopes, and the quadrupole moment of 183Ptm were thus measured. A large deformation change between 183Ptg and 183Ptm, an odd-even staggering of the charge radius, and a deformation drop from A=179 are clearly observed. Comparisons are made with microscopic theoretical predictions, in particular Hartree-Fock-Bogoliubov calculations using the Gogny force. (APS)