材料期刊网

The spin Hamiltonian parameters (g factors g(parallel to), g(perpendicular to) and the hyperfine structure constants A(parallel to), A(perpendicular to)) and the local structures for the two tetragonal Cu(2+) centers I and II in Ca(OH)(2) are theoretically studied from the perturbation formulae of these parameters for a 3d(9) ion under tetragonally elongated octahedra. The [Cu(OH)(6)](4-) clusters on the substitutional Ca(2+) site are found to suffer the relative elongations by about 0.083 angstrom and 0.065 angstrom for centers I and II, respectively, along the C(4) axis due to the Jahn-Teller effect. The above etragonal elongations may entirely depress the original trigonal distortion of the host Ca(2+) site in Ca(OH)(2). The calculated spin Hamiltonian parameters based on the above Jahn-Teller elongations show good agreement with the experimental results. The EPR spectra and the local structures for the two centers are compared with one another.