Origin of the electric hexadecapole isomer in ⁹³Mo

2025/10/25 by Maheshwari, B., Van Isacker, P., Walker, P. M.
#FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th)

paper · doi:10.48550/arxiv.2510.22352

Abstract

We present a shell-model analysis of ⁹³Mo to investigate the unusual behavior of its 21/2⁺ isomer -- a prominent candidate for nuclear excitation by electronic capture. This state is unique as its decay is dominated by a slow electric hexadecapole E4 transition, while the typically much faster electric quadrupole E2 decay path is energetically forbidden. We investigate the microscopic origin of this phenomenon by examining in detail the structure of the wave functions of the initial and final states, and the E4 transition matrix elements. This analysis of ⁹³Mo is contrasted with that of its particle-hole conjugate, ⁹⁹Cd, where such an E4 transition is absent.

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