Paramagnetic Resonance of Mn2+ in Single Crystals of CuCl

Paramagnetic resonance absorption by Mn²⁺ ion in single crystals of CuCl has been investigated at room temperature. High‐purity CuCl was obtained by distillation of reagent‐grade powder in vacuum. Crystals were grown from the vapor. The Mn²⁺ impurity ion was introduced by diffusion of MnCl₂ into the CuCl crystals. The resonance spectra consisted of the six hyperfine lines which result from the interaction of the 3d⁵ electrons with the Mn nucleus. The linewidths were 15, 12, and 10 G (±0.3 G) between the first‐derivative extrema for the transitions corresponding to $\mathrm{m=\pm }\frac{5}{2},\frac{3}{2},\frac{1}{2}$ , respectively. No fine structure was observed. These results are described by the spin Hamiltonian H=gβH·S+AI·S in which $\mathrm{S=}\frac{5}{2}$ , $\mathrm{I=}\frac{5}{2}$ , and g and A are both isotropic with g=2.0015±0.0010, | A |=(73.3±0.3)×10⁻⁴ cm⁻¹. A comparison of this value of | A | with values of | A | for Mn²⁺ impurity in a representative series of crystals with diamond and zincblende structures and with some crystals which have nearly ideal ionic bonds indicates a degree of covalency which could account for the tetrahedral coordination of the CuCl bond.