EPR Theoretical Study Of Lattice Local Structure In CaCO₃:Mn～(2+) System

The crystal CaCO₃ doped with the transition-metal ion Mn²⁺ has caused considerable interest of people in the recent decades. However, how to determine the local lattice structure of CaCO₃:Mn²⁺ systems still a problem needing to be solved. Therefore, the research on the local lattice structure becomes a very important scientific issue. In the present paper, we first introduce the method of building complete energy matrix of d⁵ configuration ion with a trigonal symmetry as well as EPR theory. By diagonalizing the complete energy matrix, we calculate the ground-state zero-field splitting of CaCO₃:Mn²⁺ system in the single crystal and the ostracum layer of operculum of fresh water snail P. globosa simultaneity. The result shows that the distortion is compressed distortion in above both cases. From this, we get an important conclusion: when Mn²⁺ ion doped in the CaCO₃ crystal, it will substitute the location of Ca²⁺ ion, thus there will be a compressed distortion along the C₃ axis in the local lattice structure.