Magnetic Moment Of The 11/2(-) Isomeric State In Mo-99 And Neutron Spin G Factor Quenching In A Approximate To 100 Nuclei

The gyromagnetic factor of the low-lying E-x = 684.10(19) keV isomeric state of the nucleus Mo-99 was measured using the time-dependent perturbed angular distribution technique. This level is assigned a spin and parity of J(pi) = 11/2(-), with a half-life of T-1/2 = 742(13) ns. The state of interest was populated and spin-aligned via a single-neutron transfer on a highly enriched Mo-98 target. A magnetic moment mu(expt.) = -0.627(20)mu(N) was obtained. This result is far from the Schmidt value expected for a pure single-particle nu h(11/2) state. A comparison of experimental spectroscopic properties of this nucleus is made with results of multishell Interacting boson-fermion Model (IBFM-1) calculations. In this approach, the J(pi) = 11/2(-) isomeric state in Mo-99 has a pure nu h(11/2) configuration. Its magnetic moment, as well as that of other two excited states could be reasonably well reproduced by reducing the free neutron spin g factor with a quenching factor of 0.45. This low value is not appropriate only for this case, similar values for the quenching factor being also required in order to describe magnetic moments in other nuclei from the same mass region.