| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1493501 | Optical Materials | 2016 | 7 Pages |
•First crystal field analysis of the Mn4+ energy levels in the commercial MFG phosphor was performed.•Site occupancy problem for the Mn4+ impurity was solved.•Mn4+ energy levels in all possible sites were calculated.•The 2E–4A2 emission transition occurs at the highest energy in MFG among all known oxides.
This is the first attempt to provide detailed crystal field analysis of the Mn4+ energy levels in the commercial magnesium fluorogermanate (MFG) phosphor. The energy levels of the Mn4+ ion (3d3 configuration) were calculated for all available sites in the lattice and the results compared with the experimental spectroscopic data. It is concluded that the Mn4+ ions prefer to occupy the sixfold coordinated Ge1 and Mg2 sites of the MFG lattice. The ligand of the Ge1 and Mg2 sites is oxygen [Ge(1)O6 and Mg(2)O6]. The incorporation of fluorine ions in the host lattice does not change the covalence of the Mn4+ bonding. This can be understood on the basis of our computational result which focuses on the distribution of the Mn4+ ion among the available lattice sites.
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