The role of N-14 and C-13 hyperfine structure in characterizing point defects in diamond

Hyperfine structure (hfs), of either C-13 or N-14, observed in the electron paramagnetic resonance (EPR) spectrum, has been a remarkably powerful indi cator of the models of paramagnetic defects in diamond. It has often been v aluable or necessary to use the much higher resolution of electron nuclear double resonance (ENDOR). Measurements of hfs have recently allowed conside rable progress in understanding the nature of defects which have been uncha racterized for many years. A rich variety of defects involving up to at lea st N-14 atoms, which readily substitute for C atoms, has been found in diam ond. The role of 14N hfs is reviewed in solving problems where different as pects are relevant. The use of synthetic diamond, enriched by up to 10% in C-13, has greatly facilitated the construction of models for centres produc ed by radiation damage, where the only information is from C-13 hfs. Both N -14 and C-13 hfs have confirmed models of Ni related centres.