EPR and optical study of Mn2+ doped ammonium tartrate single crystals

EPR study of Mn2+ doped ammonium tartrate single crystals is carried out at room temperature. The spin Hamiltonian parameters are: gx = 1.9225 ± 0.0002, gy = 1.9554 ± 0.0002, gz = 2.1258 ± 0.0002, A=(78±2)×10−4 cm−1, B=(75±2)×10−4 cm−1, D = (191 ± 2) × 10−4 cm−1, E = (61 ± 2) × 10−4 cm−1 and a = (22 ± 1) × 10−4 cm−1 for site I and gx = 1.9235 ± 0.0002, gy = 1.9574 ± 0.0002, gz = 2.0664 ± 0.0002, A=(78±2)×10−4 cm−1, B=(75±2)×10−4 cm−1, D = (180 ± 2) × 10−4 cm−1, E = (57 ± 2) × 10−4 cm−1 and a = (22 ± 1) × 10−4 cm−1 for site II, respectively. The observed optical bands are fitted with inter-electronic repulsion parameters (B and C), crystal field parameter (Dq) and Trees correction (α) and the values found are B = 752, C = 2438, Dq = 765 and α = 76 cm−1. The data obtained are further used to discuss the surrounding crystal field and the nature of metal–ligand bonding in the crystal.