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.