ased on the combination of the point-charge-model and the concept of effective bond valence

a new theory of point-charge-effective-valenc was developed.On the basis of this model

the variations of electric field gradient and quadrupole splitting on different Fe sites with the displacement of Fe dopant in Fe-doped Y-124 oxide superconductor are studied.According to quadrupole splittings obtained by Mossbauer spectroscopy

it can be deduced that the displacement of Fe3+ ions from the Cu-O2 plane are 0.0195nm for Fe-O five coordination and 0.0395nm for Fe-O six coordination

respectively.