Combinedatomic–nuclear decay

Abstract

We analyzed in details the combined decay of the atomic-nuclear state, which consists of the excited 3/2⁺ level of ₆₃¹⁵³Eu and K hole, formed in the K capture by ¹⁵³Gd. This decay proceeds in two stages. First, the nucleus transfers its energy to 2p electron, which flies into the continuum spectrum, and then returns into 1s hole, emitting γ quantum with the energy equal to the sum of energies of the nuclear and atomic transitions. We estimated the decay probability to be 2.2 × 10⁻¹³, that is much less than the recent experimental findings.