Optical absorption of LiNaGe4O9:Mn crystal
The paper reports the results of optical absorption spectra studying in LiNaGe4O9 crystal doped with Mn. It is shown that Mn impurity causes the appearance of the additional absorption bands. The intensities of these bands change in different ways in the range of the ferroelectric phase transition. Semi-empirical version of the crystal field theory is used to discuss localization and charge state of Mn impurity ions in the LiNaGe4O9 structure.