EPR and optical study of Mn2+-doped lithium hydrogen oxalate monohydrate single crystals

EPR study of Mn2+-doped lithium hydrogen oxalate monohydrate single crystals are done at room temperature. The Mn2+ spin-Hamiltonian parameters are evaluated employing a large number of resonant line positions observed for different orientations of the external magnetic field. The values of g, A, B, D, E and a are 1.9942±0.0002, 114±2×10−4, 103±2×10−4, 180±2×10−4, 57±2×10−4 and 7±1×10−4 cm−1, respectively. The optical absorption study of the crystal is also done. The observed bands are assigned as transitions from the 6A1g(S) ground state to various excited quartet levels of Mn2+ ion in a cubic crystalline field. These bands are fitted with four parameters, inter-electronic repulsion parameters (B and C), crystal field parameter (Dq) and Tree's correction (α). The values found for the parameters are B=814 cm−1, C=2255 cm−1, Dq=780 cm−1, and α=76 cm−1. On the basis of the data obtained, the surrounding crystalline field and the nature of metal-ligand bonding are discussed.