Abstract
The MSXα method has been used to calculate the s-electron densities at the nucleus for tetrahedrally coordinated ferric iron, (FeO4)5−, comparing the observed increase in isomer shift values with increasing Fe-O separation. The results give an isomer shift calibration constant of −0.3 (a.u. mm×s−1) assuming a constant ratio for the iron and oxygen sphere radii for the different polyhedra sizes. It is suggested that increasing bonding distances in tetrahedral coordination polyhedra are the dominant factors determining the value of the isomer shifts in Fe-Mg-silicates.
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Tang Kai, A., Annersten, H. & Ericsson, T. Molecular orbital (MSXα) calculations of s-electron densities of tetrahedrally coordinated ferric iron: Comparison with experimental isomer shifts. Phys Chem Minerals 5, 343–349 (1980). https://doi.org/10.1007/BF00307543
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DOI: https://doi.org/10.1007/BF00307543