Theoretical Investigations of the EPR Parameters for Three Tetragonal Centers in CsCl:Cr3+ Crystal

The electron paramagnetic resonance parameters zero-field splitting D and g factors g‖ and g⊥ of three tetragonal centers in CsCl: Cr3+ crystal at room temperature have been investigated by a two-spin-orbit (S. O.)-coupling parameter model. In this model, the contributions arising from the S. O. coupling of the central d3 ion and the ligands are included. For center III, the very small D of the [CrCl6]3− cluster may be due to the displacement (≈ 0.506 Å) of the two substitutional Cl− ions along the tetragonal (C4) axis. For the centers I and II, the relatively larger D results from the contribution of two or one water molecules, i. e., corresponding to [CrCl6−n(H2O)n]n−3 with, n = 2 or 1 along the C4 axis, respectively. The reasonableness of the theoretical results is discussed.