EPR and Optical Absorption Study of Mn~(2+)Doped Lithium Potassium Sulphate Single Crystals

摘要

EPR study of Mn~(2+) doped lithium potassium sulphate (LiKSO_4) single crystals is carried out at room temperature. The Mn~(2+) spin Hamiltonian (SH) parameters are evaluated using positions of a large number of resonance lines observed for different orientations of the external magnetic field. The estimated SH parameters are: g = 1.9986 ? 0.0002 (dimensionless), D = 244 ? 2, E = 76 ? 2, a = 4 ? 1, A = 118 ? 2 and B = 105 ? 2 (in 10~(-4) cm~(-1)), for site I and g = 2.0016 ? 0.0002 (dimensionless), D = 231 ? 2, E = 68 ? 2, a = 7 ? 1, A = 97 ? 2 and B = 86 ? 2 (in 10~(-4) cm~(-1)), for site II. The optical absorption study of the crystal is also carried out at room temperature. The observed bands are assigned to the transitions from the ~6A_(1g)(S) ground state to various excited states of Mn~(2+) ion. These transitions are matched within the crystal field framework using the inter-electronic Racah parameters (B and C), cubic crystal field parameter (Dq), and Trees correction (?). The energy levels are calculated using the crystal field analysis (CFA) computer package, whereas the parameter values are obtained using approximated analytical expressions as: B = 842, C = 2277, Dq = 745, and ? = 76 cm~(-1). On the basis of the data obtained the surrounding crystal field and the nature of metal-ligand.