Local electric field properties in K2ZnCl4 studied by magnetic resonance and Moessbauer spectroscopy

The local electric properties at K and Zn sites in the normal, incommensurate and commensurate phases of K2ZnCl4, as derived from a numerical computation of the lattice contribution to the electric potential V(r), electric field intensity E(r) and electric field gradient tensor Vαβ(r) are reported. The numerical data obtained at each cation position were correlated with the experimental 39 K NMR, Cu2+ EPR and 57 Fe Moessbauer results in pure and doped K2ZnCl4. The electric field gradient (efg) of the K+, Cu2+ and Fe3+ ions is directly related to the crystal field parameter. By this comparison, on computations done in the ionic fractional charge and relaxed lattice approximations the insertion of probe-species of ion and copper ions be on off-centre Zn sites is proposed. The 39 K-efg-tensor calculation of the incommensurate phase fit well the NMR data reported recently. (authors)