Electronic Structure of the Centers in ZnS

A model of the common sulfide luminescent centers is proposed. The mutual perturbation of crystal eigenstates and transition-metal (activator) d eigenstates is assumed to give rise to the excited and unexcited eigenstates of the center. For substitutional Cu⁺(d¹⁰) in zincblende, zeroth order crystal field theory predicts that two sets of occupied center ground-state levels (T₂ and E) originating from d¹⁰ will exist. Additional level splittings result from (a) the spin-orbit effect, and (b) axial crystal field splittings in wurtzite. Experiments on visible and infrared, excitation and emission, are used to make tentative assignments of magnitude of level splittings.