Theoretical study of electron paramagnetic resonance spectrum and local lattice distortion for Mn2+ in Al2O3:Mn2+ system

Electron paramagnetic resonance spectrum and local lattice distortion for Mn2+ ion in Al2O3:Mn2+ system have been studied by means of the complete energy matrices for electron–electron repulsion, spin–orbit coupling and ligand–field interactions. It is shown that the local lattice structure around Mn2+ ion in Al2O3:Mn2+ system exhibits an elongation distortion in the local lattice structure. The elongation distortion may be ascribed to the facts that the radius of Mn2+ is larger than that of the host ion Al3+, and the Mn2+ ion will push the oxygen ligands outwards. By simulating the second- and fourth-order EPR parameters D and (a−F  ) simultaneously, the bond length of the upper and lower oxygen triangle R1=2.112–2.137A, R2=2.003–2.028A, and the angles between the chemical bond length and C3 axis θ1=52.944–52.950°θ1=52.944–52.950°, θ2=57.910–57.960°θ2=57.910–57.960° are determined. Furthermore, the displacements ΔZ1=0.2225–0.2345A for transition-metal ion and ΔZ2=0.171–0.198A for the distance variation between the two oxygen planes are derived.