The nitrogen content of type Ib synthetic diamond

The concentration of single nitrogen atoms in type Ib synthetic diamond has been measured, by electron paramagnetic resonance and by inert-gas fusion, as a function of the strength of the infrared absorption produced by these centres. The two methods yield, in good agreement, values of 22·0 ±.1·1 at. p.p.m. and 20·6±1·5 at. p.p.m. respectively, for an absorption coefficient of 1cm −1 at 1130 wavenumbers. These values agree tolerably well with an earlier value of 25 at. p.p.m./cm−1 given by others, so calling into question the generally accepted data pertaining to the strength of the infrared absorption produced by the A centres, or nitrogen pairs, found in type Ia (natural) diamond.