New Evidence for the Two-ElectronOState in GaP

Abstract
Optically detected magnetic resonance in oxygen-doped GaP shows that the infrared emission at 0.84 eV and its phonon replicas are due to a spin-triplet to -singlet transition of the two-electron state of oxygen. The resonance data also show that the two-electron center has axial symmetry along the [110] axis, indicating that after capturing the second electron a strong lattice relaxation takes place.