Large deformation change in iridium isotopes from laser spectroscopy

Laser spectroscopy measurements have been performed on neutron-deficient iridium isotopes. The hyperfine structure and isotope shift of the optical Ir I transition 5d76s2 4F9/2→5d76s6p 6F11/2 have been studied for the 182–189Ir, 180Irm and 191,193Ir isotopes. The nuclear magnetic and quadrupole moments were obtained from the hyperfine splitting measurements and the changes of the mean square charge radii from the isotope shift measurements. A large deformation change between 187Ir and 186Ir and between 186Irm and 186Irg has been observed.