Magnetic moment of the 11/2− isomeric state in Mo99 and neutron spin g

Abstract

The gyromagnetic factor of the low-lying Ex = 684.10(19) keV isomeric state of the nucleus 99 Mo was measured using the Time Dependent Perturbed Angular Distribution technique. This level is assigned a spin and parity of J π = 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 an highly enriched 98 Mo target. A magnetic moment µexp. = −0.627(20)µN was obtained. This result is far from the Schmidt value expected for a pure single-particle νh 11/2 state. A comparison of experimental spectroscopic properties of this nucleus is made with results of multi-shell Interacting Boson-Fermion Model (IBFM-1) calculations. In this approach, the J π = 11/2 − isomeric state in 99 Mo has a pure νh 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.

Nuclear DFT analysis of electromagnetic moments in odd near doubly magic nuclei

“…to test our description of microscopic properties such as those of valence nucleons [3][4][5][6][7][8] and the role of nuclear electroweak currents [9,10]. Although great progress was achieved in the description of electromagnetic properties of light nuclei [10] and experimental trends in certain isotopic chains, a unified and consistent description of nuclear electromagnetic properties remains an open challenge for nuclear theory.…”