Nuclear g factors and structure of high-spin isomers in ^190,192,194Pt and ^196,198Hg

The integral perturbed angular distribution (IPAD) method in an external magnetic field has been used to measure the g factors of isomers in the ^190,192,194Pt and ^196,198Hg nuclei, populated in the (α, 2n)-reaction. The results are as follows: ¹⁹⁰Pt, g(12⁺) = -0.17(12), g(10^- = -0.0016(36), g(7^-) = +0.62 (9); ¹⁹²Pt, g(12⁺) = -0.18(9), g(10^-) = -0.0012(10), g(7^- ) = 0.48(12); ¹⁹⁴Pt, g(12⁺, new assignment) = -0.17(7), g(7^-) = +0.26(8); ¹⁹⁶Hg, g(12⁺ and 10⁺) = -0.19(6), g(7^- = -0.030(17); ¹⁹⁸Hg, g(12⁺ and 10⁺ = -0.18(8), g(7^- = -0.033(14). The intrinsic structure of the isomers is discussed. The 12⁺ states have the rotational-aligned (νi_13/2^-2 structure. The missing rotation-aligned (νi_13/2^-2) 12⁺ state is suggested to be isomeric in ¹⁹⁴Pt (instead of the 10⁺ state) and to which the g = -0.17(6) value has to be attributed. From the g factors of the 10^- states in ¹⁹⁰Pt and ¹⁹²Pt, which have the configuration ν9/2^-[505] ⊗ ν11/2⁺[615], the anomalous g_l-factor for neutrons has been derived as δg_l = -0.028(6). The trend from negative g factors of the 7^- states in the ^196,198Hg nuclei to positive values for the corresponding states in the ^190,192,194Pt nuclei indicates a change in the intrinsic structure of the lowest negative-parity bands, from mainly (νi_13/2^-2) in Hg to mainly (πh_11/2^-2) in Pt.