Unified research of the optical and EPR spectral data for the trigonal Cr3+ centers in emerald crystals

First-Principles Study of Optical Absorption Energies, Ligand Field and Spin-Hamiltonian Parameters of Cr3+ Ions in Emeralds

“…Considering that electronic energy levels, local properties, and structures of the Cr 3+ impurity centers in emeralds are well studied using various experimental techniques, a number of theoretical studies that analyze these data have appeared in the literature. ,, In general, most theoretical interpretations of the experimental results regarding energy levels, ligand-field parameters (LFPs), and spin-Hamiltonian parameters (SHPs) have been accomplished in the framework of semiempirical crystal-field theory (CFT) or ligand-field theory (LFT). − Although such approaches are useful for studying materials with experimentally known properties, it is difficult to apply LFT in a predictive fashion toward the development of new materials. Fortunately, ab initio quantum mechanical calculations have made enormous progress over the course of the past two decades in their predictive capabilities.…”