Internal-conversion coefficient determination of odd parity for the 108.8-keV first-excited state of 91Rb
Internal-conversion coefficients of the 108.8-keV transition in the decay of 91Kr and the 93.6-keV transition in the decay of 91Rb were measured by the electron-to-γ-ray ratio method using a high-resolution magnetic spectrometer and by the x-ray-to-γ-ray ratio method using a low-energy photon spectrometer. The 93.6-keV transition was found to be pure E2. The 108.8-keV transition from the first-excited state of 91Rb was found to be pure M1, which determines the parity of this state as odd, as expected from spherical shell-model considerations, and contradicts a recently reported assignment of even parity for this state. RADIOACTIVITY 91Kr, 91Rb [from 235U(n, f)] measured E and I for low-energy ce's, x rays, γ's π2 magnetic spectrometer, Ge(Li); deduced ICC, transition multipolarities; mass-separated A=91 activity.