New S = 1 EPR Center in Irradiated Diamond

Electron spin resonance studies have been made of natural diamond crystals electron‐irradiated at room temperature. A radiation‐induced spectrum is identified as arising from a new anisotropic S=1 center. The S=1 center is characterized by: $g_1{\text{=2.0026,\hspace{0.17em}g}}_2{\text{=2.0021,\hspace{0.17em}g}}_3{\text{=2.0016;\hspace{0.17em}D}}_1{\text{=∓27(10}}^{\text{−4}}\hspace{0.17em}{\mathrm{cm}}^{\text{−1}}{\mathrm{),\hspace{0.17em}D}}_2{\text{=∓25(10}}^{\text{−4}}\hspace{0.17em}{\mathrm{cm}}^{\text{−1}}{\mathrm{),\hspace{0.17em}D}}_3{\text{=±51(10}}^{\text{−4}}\hspace{0.17em}{\mathrm{cm}}^{\text{−1}})$ . Associated with each resonance line are four sets of weaker lines which are ascribed to hyperfine interaction with ¹³C (I=½, 1.1% abundant) at four nonequivalent sets of sites. The identity of the defect has not yet been established.