Heating effects on the optical absorption spectra of irradiated, natural spodumene

We have studied the lilac spodumene through optical absorption and electron paramagnetic resonance measurements. The effects of increasing doses of γ-rays from 60Co on the spectra were determined. The following absorption bands were analysed: 10500, 15600 and 21500cm−1 assigned to d-d transitions of Mn3+ (G); 11000, 12000, 18600 and 22000cm−1 assigned to d-d transitions of Mn3+ (L). The G and L refer to distinct octahedral sites, both tetragonally distorted with the axial Mn–O bonds extended (Jahn-Teller effect).