A center, in thermochemically reduced crystals, which was associated with N was studied by using electron paramagnetic resonance techniques. The spectrum of this center exhibited axial symmetry, with 3-fold hyperfine splitting. The spin-Hamiltonian parameters for this center were S = ½, I = 1, g = 1.9702, g|| = 1.9436, |A| = 5.4MHz, and |A||| = 3.0MHz, with the symmetry axis along the <100> direction. A possible candidate for this center was [FN]0. This was an F+ center which was next to a substitutional N impurity. This center was stable at temperatures of between 13 and 140K.

S.C.Ke, H.T.Tohver: Physical Review B, 1994, 50[21], 16060-2