Optical detection of magnetic resonance in MgO:Cr³⁺. II. Cr ³⁺ ions in tetragonal symmetry sites

For pt.I see ibid., vol.13, p.2191 (1980). Optical studies of magnetic resonance in the excited state of Cr³⁺ ions in tetragonal symmetry sites are reported. The observed spectra are discussed in terms of the calculated selection rules for circularly polarised fluorescence, and it is shown that the results are consistent with thermalisation in the excited spin states. The measured g tensor is that which is to be expected from a crystal-field split ²E_g state in which the mod ²E_gV) orbital lies lowest.