Electron densities at the nucleus are estimated from measurements of the change in electron capture rate of /sup 52/Fe in different iron compounds. This leads to a calibration constant alpha for the /sup 57/Fe isomer shift: alpha =-0.31+/-0.04 a/sub 0/ /sup 3/ mm s/sup -1/.
Ladrière, J., Cogneau, M., Meykens, A., Coussement, R., Boge, M., Auric, P., Bouchez, R., Benabed, A., & Godard, J. (1979). Isomer shift calibration of /sup 57/Fe by life-time variations in the electron-capture decay of /sup 52/Fe. Journal de Physique. Colloque, Vol. 40, p. C2/20-C2/22.