Exchange interactions in nearest-neighbor Cr3+ ion pairs in LiGa5O8:Cr3+

Additional transitions which appear in the absorption and luminescence spectra of heavily doped ( 1 at.%) LiGa5O8:Cr3+ originate on nearest-neighbor Cr-Cr ion systems. By analyzing these spectra at different temperatures, values are obtained for the exchange parameters in the ground electron state; j=-35.8 cm-1 and j=-1.4 cm-1. These are shown to be entirely consistent with the systematics of nearest-neighbor interactions in other dilute and concentrated chromium spinel systems.