The hyperfine structure and isotope shifts of /sup 189m,191m,193m/Tl have been measured by means of collinear fast-beam/laser spectroscopy. Deformations for the 9/2/sup -/ isomers are determined to be larger than for the 1/2/sup +/ ground state and increase with decreasing neutron number. Despite different deformations, rotational properties are nearly identical in /sup 185-199/Tl. Microscopic theory ascribes this to a systematic balance between changing deformation and neutron pairing. 8 refs., 4 figs.
DOE contract number: AS05-76ER04936 OSTI Identifier 6095619 Research organization: Oak Ridge Associated Universities, Inc., TN (USA). Research organization: Tennessee Univ., Knoxville (USA). Dept. of Physics.