The Mossbauer and magnetic resonances investigations of structural phase transitions in K2ZnCl4 crystals

The experimental data carried out by Mossbauer and magnetic resonances inve stigations of the structural phase transitions in K2ZnCl4 crystals are disc ussed by a simple electrostatic model, calculating, the lattice contributio ns to the local electric potential V(r), electric field intensity E(r) a,nd electric field gradient tensor, V-alpha beta(r) and taking into account bo th the fractional electric point charges and rigid lattice approximations. The validity of the model is proved by a good fit of the computing results and experimental data of quadrupole splitting parameters at K Bites obtaine d by K-39-NMR methods in high temperature incommensurate phase (similar to Pnam symmetry). The experimental results obtained by Mossbauer and EPR meth ods in commensurate phase (Pna2(1) symmetry) of iron and copper doped K2ZnC l4 crystals are explained by relaxing the rigid lattice approximation. The insertion of probe ions appear to be done on not-exactly-Zn2+ site.