LAUSR

Neutron-activated sources of Ru and Pd both share the isomeric first-excited state in Rh as a daughter product. From independent measurements of both decays, we have measured the K-shell and total internal conversion coefficients, αK and αT , for the 39.8-keV E3 transition, which de-excites that state in Rh, to be 141.1(23) and 1428(13), respectively. When compared with Dirac-Fock calculations, our new results disagree with the version of the theory that ignores the Kshell atomic vacancy, which is consistent with our conclusion drawn from a series of measurements on high multipolarity transitions in nuclei with higher Z. Calculations that include the atomic vacancy indicate that the transition actually has a small M4 component with mixing ratio δ = 0.023(5).