Blue cathodoluminescence related to defect center in smithsonite

Abstract

Smithsonite occasionally exhibits a characteristic blue emission, known as cathodoluminescence (CL), which can be assigned to a lattice defect center by CL spectral analysis. The intensity of this emission is reduced at higher temperatures, suggesting a temperature quenching phenomenon. The activation energy in the quenching process was evaluated by a least -square fit of the Arrhenius plots using the integrated intensity of the emission component, and was found to be ~ 0.03 eV for the defect center. According to the Mott -Seitz model, the quenching process can be interpreted by an increase in non -radiative transition at higher temperatures. The value of the activation energy for a blue emission caused by the defect center corresponds to the vibration energy of the O -Zn -O bending mode in the lattice. It implies that the temperature quenching energy might be transferred as a phonon to the specific lattice vibration.

Cathodoluminescence of calcite decomposed from dolomite in high–temperature skarn

“…There is almost nothing about detail information of defect centers ('back ground blue') such as wavelength of the emission peak (e.g., Machel et al, 1991). Recently, Nishido et al (2013) confirmed a blue emission in zinc carbonate of smithsonite as a defect center, of which energy corresponds to 3.30 eV, involved with 3.83 eV at low temperature. Therefore, the emission component at 3.30 eV in calcite A can be assigned to defect center re- lated to common features of calcite-type carbonate, though the other one at 2.67 eV is not possible to be identified as of now.…”