Correlation of spectroscopic properties and substitutional sites of Cr3+ in aluminosilicates: I. Kyanite

Abstract

Using the superposition model in conjunction with our crystal field analysis package recently developed for 3d ions doped at arbitrary low symmetry sites in crystals, the energy levels and statevectors have been predicted within the whole 3d3 configuration of Cr3+ at the four possible triclinic sites in kyanite (Al2O3∶SiO2). The values of the ground state zero-field splitting for each of the four Al sites are evaluated. The splittings of the lower excited state 2E as well as the admixture of 4T2 state into 2E have also been determined. The predicted results are compared with the available experimental data on the four possible, but so far not uniquely identified, substitutional Cr3+ sites in kyanite thus enabling correlation of the spectroscopic properties and substitutional sites.