Isotope shifts of neutron-deficient gold isotopes with 193≧A≧190

The isotope shift between197Au (stable) and the radioactive Au isotopes190Au,191Au,192Au and193Au were determined by resonance fluorescence spectroscopy in the 6s2S1/2–6p2P1/2.λ=267.6nm line. The unstable Au isotopes were produced at the ISOLDE mass separator at CERN. The nuclei were investigated semi on-line in a resonance vessel, heated to 1,400°C. The results areδν190,197=−11.12(39) GHz,δν191,197=−9.67(12) GHz,δν192,197=−8.32(15) GHz,δν193,197=−6.29(11) GHz, corresponding to a change of the mean-square charge radius byδ〈r2〉190,197 =0.261(12) fm2,δ〈r2〉191,197=0.227(5) fm2,δ〈r2〉192,197=0.195(5) fm2,δ〈r2〉193,197 =0.148(4) fm2.