Pressure-induced changes in the energetic structure of the 3d3 ions in solid matrices

The results of high-pressure spectroscopy of Cr3+ and Mn4+ ions in solids are revised. We discuss the influence of external pressure on compression of ion–ligands systems, pressure-induced 4T2–2E level crossover, R-lines pressure shift and influence of pressure on the R-lines emission lifetime. The model of energetic structure of the octahedrally coordinated 3d3 ion that includes electron–phonon and spin–orbit interaction is considered and used for interpretation of the results of high-pressure spectroscopy, especially for quantitative analysis of lattice disorder and crystal field distribution in crystal.