EQUILIBRIUM FRACTIONATION OF THE IRON ISOTOPES: ESTIMATION FROM MOSSBAUER SPECTROSCOPY DATA

Abstract

A close relationship between the second-order Doppler shift (SOD) of the Mossbauer resonant recoil-free frequency and the equilibrium stable isotope fractionation has been established. The reduced isotopic partition function ratios (β-factors) of the iron isotopes for a set of substances has been evaluated from appropriate experimental data on the SOD. The extent of the equilibrium stable iron isotope fractionation has been estimated. The equilibrium fractionation of the iron isotopes is notable at temperatures up to 1000 K and may be essential not only at surface conditions but in geothermal and metamorphic processes in the Earth's crust as well. This opens up new possibilities for applications of iron isotope fractionation in geochemistry and cosmochemistry.