Density functional theory study of substitutional oxygen in diamond
  A few studies have been recently presented for the existence of oxygen in diamond, for example, the N3 EPR centres have been theoretically and experimentally assigned the model made up from complex of substitutional nitrogen and substitutional oxygen as nearest neighbours. We present ab initio calculations of substitutional oxygen in diamond in terms of stability, electronic structures, geometry and hyperfine interaction and show that substitutional oxygen with C$_{2v}\,$, $S=1$ is the ground state configuration. We find that oxygen produces either a donor or acceptor level depending on the position of the Fermi level. 
K.M. Etmimi, P.R. Briddon, A.M. Abutruma, A. Sghayer, S.S. Farhat
cond-mat.str-el cond-mat.mtrl-sci