Luminescence of Mn4+ in the orthorhombic perovskite, LaGaO3

The optical properties of Mn4+ (3d3) in the orthorhombic perovskite, LaGaO3 are investigated. The Mn4+ energy levels are calculated using the exchange charge model of crystal-field theory. The calculated Mn4+ energy levels are in good agreement with the experimental spectroscopic data. The results of our calculations yield the crystal-field splitting and Racah parameters of Dq=1926 cm−1, B=780 cm−1 and C=2878 cm−1, with C/B=3.7. The emission spectrum is assigned on the basis of the zero phonon line corresponding to the 2Eg→4A2g transition and its vibrational sidebands. A comparative study of the variation in the crystal-field splitting and the Mn4+ 2Eg energy level position in materials with the perovskite structure is also presented.