Mossbauer emission spectra of a Co-57:ZnSe powder source at low temperature
exhibit the overcompensated Fe1+ state of the nucleogenic daughter ion gen
erated as an after effect of the Co-57(EC)Fe-57 decay. We analyse to what e
xtent the model of competing acceptors is able to account for the formation
and fraction of Fe1+ and present evidence for the role of hole trapping by
zinc vacancies.