EPR and optical absorption study of Cu2+-doped lithium potassium sulphate single crystals

EPR spectra of Cu2+ ion doped in lithium potassium sulphate single crystal at room temperature are reported. The observed spectra are fitted to a spin Hamiltonian of orthorhombic symmetry with Cu2+ (site I) gx=2.0930, gy=2.1421, gz=2.2900 (±0.0002) and Ax=85, Ay=89, Az=184 (±2×10−4 cm−1); Cu2+ (site II) gx=2.0795, gy=2.1580, gz=2.2876 (±0.0002) and Ax=93, Ay=95, Az=189 (±2×10−4 cm−1); respective errors given in brackets. Copper enters the lattice substitutionally and is trapped at two magnetically inequivalent sites. The ground state wave function of the Cu2+ ion in this lattice is determined as predominantly |x2−y2〉. The g-factor anisotropy is calculated and compared with the experimental value. The optical absorption of the crystal at room temperature is also recorded. Further, with the help of the optical absorption and EPR data, the nature of bonding in the complex is discussed.