Paramagnetic Resonance Spectrum of O− Trapped in KCl, RbCl, and KBr

The impurity ion O− has been introduced into KCl, RbCl, and KBr and detected at 4°K by EPR spectroscopy. The center has orthorhombic symmetry. A quantitative understanding of the g factor and of the O17 hyperfine structure was obtained with the aid of equations derived in a recent analysis of the an-alogous S− impurity. The hyperfine splitting was described by the atomic parameters ψ2(0), 〈r−3〉l, and 〈r−3〉s. The present results indicate that in an earlier investigation of O− trapped in alkali iodide crystals erroneous values were obtained for these parameters.