Reply to "Comment on 'Mossbauer effect study of filled antimonide skutterudites' "

The temperature dependence of the isomer shift of alpha-iron between 4.2 an d 990 K and of Dy3Fe5O12 between 4.2 and 550 K has been analyzed in terms o f the Debye model for the second-order Doppler shift, a model in which an a dditional parameter, the effective vibrating mass, is included. This mass i s found equal to 57 g/mol in the ionic compound, Dy3Fe5O12, and equal to 60 g/mol in metallic alpha-iron. The deviation of this mass from 57 g/mol is a measure of the covalency of the metallic bonding in alpha-iron. The inade quacy of the graphical procedure proposed by Rechenberg, based on the treat ment of second-order terms in the temperature dependence of the isomer shif t, is also illustrated.