Theoretical studies of spin Hamiltonian parameters for the tetragonally elongated Cu2Â + centers in ARbB4O7 (A = Li, Na, K) glasses

► Spin Hamiltonian parameters and local structures are analyzed for Cu2 + in ARbB4O7 (A = Li, Na, K) glasses. ► The tetragonal distortion is taken into account by considering the relative axial elongation of the ligand octahedron. ► Ligand octahedra experience local bond length variations of the Jahn-Teller nature.