SPECTROSCOPIC EFFECTS OF SMALL 4T2-2E ENERGY SEPARATIONS IN 3D3-ION SYSTEMS

The energy of the **4A//2 yields **4T//2 transition of 3d**3 ions in octahedral sites decreases with increasing temperature, with a consequent reduction in the energy separation, DELTA , between **4T//2 and **2E levels. This can significantly affect the spectroscopic properties of Cr**3** plus -doped materials with small DELTA values. These materials are of interest because of their possible use in tunable laser systems. Some experimentally measured values of this shift are presented, the mixing of **2E and **4T//2 electronic-vibrational states when DELTA is small is estimated, and the effects of this mixing on the spectroscopic properties are discussed.