The 14N, 15N and 13C hyperfine interactions in the ground state of the negatively

charged nitrogen vacancy (NV−) center were investigated using electronparamagnetic-

resonance spectroscopy. The previously published parameters for the

14N hyperfine interaction do not produce a satisfactory fit to the experimental NV−

electron-paramagnetic-resonance data. The small anisotropic component of the

NV− hyperfine interaction can be explained from dipolar interaction between the

nitrogen nucleus and the unpaired-electron probability density localized on the

three carbon atoms neighbouring the vacancy. Optical spin polarization of the NV−

ground state was used to enhance the electron-paramagnetic-resonance sensitivity

enabling detailed study of the hyperfine interaction with 13C neighbours. The data

confirmed the identification of three equivalent carbon nearest neighbours but

indicated the next largest 13C interaction was with six, rather than as previously

assumed three, equivalent neighbouring carbon atoms.

Hyperfine Interaction in the Ground State of the Negatively Charged Nitrogen

Vacancy Center in Diamond. S.Felton, A.M.Edmonds, M.E.Newton, P.M.Martineau, D.Fisher, D.J.Twitchen, J.M.Baker: Physical Review B, 2009,

79[7], 075203