Magnetic Moments of the 8⁺ Isomeric States of ⁹⁰Zr and ⁹²Mo

Abstract

The g-factors of the [πg_9⁄2²]8⁺ states of ⁹⁰Zr(t_1⁄2=130 nsec) and ⁹²Mo(t_1⁄2=190 nsec) have been determined to be 1.355±0.018 and 1.409±0.016, respectively, by the time-differential spin rotation method in (α, 2n) reactions. The results together with the known g-factors in the A=88 region are compared with theoretical values derived from the M1 spin polarization and the mesonic exchange current. It turns out from the analysis that (1) the difference between the observed g-factors of the two 8⁺ states is well accounted for by the M1 spin polarization mechanism and that (2) the mesonic effect of Δg_l=0.10 and Δg_s<0 explains the absolute values of the observed moments in this region.