Paramagnetic complexes in zinc selenide crystals with iron admixture

Paramagnetic resonance of ZnSe: Fe single crystals was studied at 120 K. Parameters of the spin Hamiltonian were determined for the monoclinic dimer complex Fe$^{3+}$-Cu$^{+}$ and a second discovered Fe$^{3+}$ center, which appears due to association of the iron ion with a K$^+$ ion in a Zn$^{2+}$ position or with a zinc vacancy. Effect of illumination of the zinc selenide samples by blue, green and red light on the paramagnetic resonance spectrum was investigated.