Ruthenium (III) -doped silver bromide and silver chloride: An EPR study

Abstract

Ru3+ and Ru2+ ions are substitutionally incorporated into melt-grown crystals of AgBr and AgCl. The d5 trivalent ion predominates in samples prepared in oxidizing environments, such as Br2 and Cl2, and it has been the subject of a detailed magnetic resonance study. It is distributed between four structurally inequivalent lattice sites in both salts. These sites are distinguished by the arrangement of charge-compensating silver-ion vacancies in the two closest cation subshells. Reasonable dopant-vacancy configurations have been deduced from the EPR data.

Theoretical studies of the spin Hamiltonian parameters for the tetragonal Co4+ and Ir4+ centers in SrTiO3

“…λ pσ /S σ ≈ λ s /S s within the same σ component. Obviously, when taking S γ = λ γ = 0 and A = 0, the above formulas return to those in the absence of the ligand contributions [13,14]. ).…”

“…By considering the contributions to the spin Hamiltonian parameters from the orbital reduction (or covalency effect) and spin-orbit coupling interactions, the formulas of the anisotropic g factors and the hyperfine structure constants for the low-spin (S = 1/2) d 5 systems were obtained [13,14]. Later on, improved studies were carried out for trigonally distorted Ru 3+ clusters in garnets [15], by considering the contributions from the anisotropies of the orbital reduction effect (i.e.…”

“…The systems have the orbital triplet 2 T 2g with low spin (S = 1/2) as the ground state, where the five d electrons occupy the t 2g orbitals (corresponding to one t 2g hole) [11][12][13]. When the ligand octahedron is tetragonally elongated, the 2 T 2g state may split into one singlet 2 B 2g orbital and one doublet 2 E g , the latter lying lowest.…”

“…B 2g and 2 E g is often defined as the tetragonal distortion parameter ∆ [11,13]. In addition, inclusion of the spin-orbit coupling interactions may result in splitting of the above states into three Kramers doublets.…”

Theoretical studies of the local structures and the spin Hamiltonian parameters of the tetragonal Ru3+ centers in AgCl and AgBr

“…For example, various (tetragonal and rhombic) impurity Ru 3+ (4d 5 ) centers in AgX with Ru dopants were extensively investigated by means of EPR technique, and the spin Hamiltonian parameters, g factors and the hyperfine structure constants were also estimated [13]. These impurity centers have been ascribed to different cases of charge compensation (i.e.…”