Multi-frequency electron paramagnetic resonance studies at between 8 and 300K were made of diamonds synthesized by chemical vapour deposition and intentionally Si-doped with isotopes in natural abundance or isotopically enriched. The 29Si hyperfine structure had provided definitive evidence for the involvement of silicon in two electron paramagnetic resonance centers in diamond that were previously suspected to involve silicon: KUL1 and KUL3. Data were presented that unambiguously identified KUL1 as being an S=1 neutral Si split-vacancy (D3d symmetry) defect (V-Si-V)0, while KUL3 was shown to be (V-Si-V)0 decorated with a H atom: (V-Si-V:H)0.

Electron Paramagnetic Resonance Studies of Silicon-Related Defects in Diamond. A.M.Edmonds, M.E.Newton, P.M.Martineau, D.J.Twitchen, S.D.Williams: Physical Review B, 2008, 77[24], 245205 (11pp)