Level-crossing in chromium-doped materials

A coincidence in energy of the 2E and 4T2 excited levels of Cr3+ appears to occur in the material GSGG:Cr3+, and as a result the material exhibits a number of interesting luminescence features. The mixing of the 2E and 4T2 eigenstates by the spin-orbit coupling operator is analyzed using a simple model which takes account of the vibrational nature of the eigenstates. It is shown that this model is capable of explaining many of the observed luminescence features of the material.