Optical absorption of MgO:Mn

Wavelength-modulated absorption measurements on MgO:Mn show the presence of Mn 3+ and Mn 2+ . The lowest spin-allowed transition of Mn 3+ occurs at 520 nm. Weak bands at 301, 356, 389 and 426 nm are attributed to transitions from 6 A 1g to the 4 T 1g (P), 4 T 2g (D), 4 E g (G)+ 4 T 2g (G) and 4 T 2g (G) states of Mn 2+ , respectively. The latter band shows four zero-phonon lines with an over-all splitting of 34 cm -1 revealing a spin-orbit splitting of the 4 T 2g (G) state reduced by a factor of four by the action of a dynamic Jahn-Teller effect. Stress experiments indicate that the dominating Jahn-Teller interaction is with T 2 symmetry vibrations.