Probability of internal ionization during nuclearβdecay: Effect of final-state interaction

A full calculation of the probability of ionization of a $K$-shell electron during nuclear $\beta$ decay, including the effect of final-state interaction (direct-collision mechanism), has been carried out using nonrelativistic hydrogenic wave functions. Numerical results are presented for ${}_{28}{}^{63}{}_{}{}^{}\mathrm{Ni}$, ${}_{46}{}^{107}{}_{}{}^{}\mathrm{Pd}$, and ${}_{62}{}^{151}{}_{}{}^{}\mathrm{Sm}$; they are found to be larger than the predictions of shake-off theory by 12-15%. A comparison with other recent theoretical results is made; significant differences are found.