Analysis of the Hyperfine Interactions of the Vacancy‐Iodine Complex in ZnSe

The ESR line multiplicity of iodine containing ZnSe single crystals obtained after optical excitation is analysed by means of a spin Hamiltonian. A good fit is obtained considering Zeeman energy, hyperfine energy, quadrupole energy, and (pseudo)‐nuclear Zeeman energy with S = ½ and I = 5/2. The fact that iodine consists to 100% of the isotope 127I with I = and that the spectra are described by I = is proof that iodine is an integral part of the complex centre. This is the first time that a ligand hyperfine structure of A‐centres in ZnSe is observed and numerically analysed. Therefore, also the orientations of the different tensors in the spin Hamiltonian are determined with respect to the orientation of the complex centre. Besides the 127I ligand hyperfine structure the 77Se hyperfine and the 77Se ligand hyperfine structure are observed. From the different hyperfine parameters the distribution of the hole wave function is derived and yields ≈ 90% localisation in the sp3‐hybrid lone pair orbitals directed to the zinc vacancy.