Nuclear lifetime prolongation in resonant electron recombination processes

Ruprecht-Karls-Universita¨t,HeidelbergThe populationand lifetime of nuclear excited states areaffected by the electronic shells, especially in nuclear pr o-cesses which directly involve electrons [1]. In particular ,the lifetime of low-lying excited nuclear states can be in-creased by the process of nuclear excitation by electroncapture(NEEC)followedbyfast x-rayemission(NEECX)in highly-charged heavy ions. In the resonant process ofNEEC, the collision of an ion with a free electron leads toresonant capture into an atomic orbital with simultaneousexcitationofthenucleus[2]. Forsomeheavynuclei,NEECinto the K shell is energetically forbidden. In this case,NEEC into the L shell of bare ions will be followed by astabilizing x-ray decay that suppresses the internal conve r-sion channeland limits the nucleardecay rate to the rate,thus modifying the lifetime and population of the nuclearexcited state.We n dthat NEECX occurringin the fully ionized