Investigations of the spin-Hamiltonian parameters and tetragonal distortions due to Jahn–Teller effect for the monovalent d9 (Ni+, Pd+, Pt+) impurity centers in AgCl crystals

When the monovalent md9 ions Ni+ (3d9), Pd+ (4d9) and Pt+(5d9) substitute for the Ag+ ions in AgCl crystal, the cubic chlorine octahedron surrounding Ag+ in the host AgCl crystal distorts into the tetragonally elongated octahedron in the md9 impurity center owing to the Jahn–Teller effect. The spin-Hamiltonian parameters (g factors g||, g⊥ and hyperfine structure constants A||, A⊥) of the tetragonal md9 centers in AgCl are calculated from the high-order perturbation formulas based on the cluster approach, in which the admixture between d orbitals of dn ion and p orbitals of ligand ion via covalence effect are taken into account. From the calculations, the spin-Hamiltonian parameters of these tetragonal md9 centers in AgCl are explained reasonably and the tetragonal distortions (characterized by the tetragonal elongation ΔR = R|| − R⊥, where R|| and R⊥ denote the metal–ligand distances parallel with and perpendicular to the tetragonal axis) of these centers due to Jahn–Teller effect are obtained. The results are discussed.

Research highlights▶ The spin-Hamiltonian parameters of md9 ions Ni+, Pd+ and Pt+ substituting for the Ag+ ions in AgCl crystals are calculated. Especially for 4d9 ion Pd+ and 5d9 ion Pt+, the related study is very scarce. ▶ The calculation is using the high-order perturbation formulas based on cluster approach. The cubic chlorine octahedron in the host AgCl distorts into the tetragonally-elongated octahedron in the md9 impurity center owing to the Jahn-Teller effect. ▶ The tetragonal elongation is obtained from the calculation of spin-Hamiltonian parameters.