Note on zero-zero transitions

Zero-zero nuclear transitions have been suggested by Sachs(1) as an explanation of long lived isomers. He computed the energy spectra and transition probabilities for two-electron and two-quantum emissions. Stimulated by preliminary results of experiments by Goldhaber, Muehlhause, and Turkel(2) on the isomeric transition in Ir192 (mean life 2.16 min., energy 58 kev), which shows a continuous γ-ray spectrum in addition to conversion electrons, we have computed the γ-ray energy spectrum and lifetimes for zero-zero transitions in which one electron and one quantum are emitted. For comparison, the lifetime for the transition og→og (or ou→ou) is computed by direct emission of an electron. The analogous transition in the case og→ou is strictly forbidden.