ESR and optical study of Mn2+-doped sodium hydrogen orthophosphate dihydrate

ESR study of Mn2+-doped sodium hydrogen orthophosphate dihydrate (SHOD) single crystals is done at room temperature. The Mn2+ spin-Hamiltonian parameters have been 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: 2.0042 ± 0.0002, 86 ± 2 × 10−4 cm−1, 83 ± 2 × 10−4 cm−1, 238 ± 2 × 10−4 cm−1, 76 ± 2 × 10−4 cm−1, 13 ± 1 × 10−4 cm−1 for site I and 2.0032 ± 0.0002, 86 ± 2 × 10−4 cm−1, 83 ± 2 × 10−4 cm−1, 238 ± 2 × 10−4 cm−1, 76 ± 2 × 10−4 cm−1, 13 ± 1 × 10−4 cm−1 for site II, 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 a Mn2+ ion in a cubic crystalline field. These bands are fitted with four parameters B, C, Dq and α and the values found for the parameters are B = 777 cm−1, C = 3073 cm−1, Dq = 755 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.