Superposition model analysis of in sodium ammonium sulphate dihydrate

Abstract

This paper discusses the application of the superposition model of Newman to studies of local distortions around ions doped into sodium ammonium sulphate dihydrate. It is shown that local distortions and a model for the charge compensation mechanism can be derived from the standard use of the superposition model for two of the sites observed ( and ). The calculations were carried out for the spin Hamiltonian parameters measured at temperatures both above and below the phase transition detected at . It is shown that the phase transition induces a substantial decrease in the metal-ligand distance in octahedra.