The relationship between infrared absorption and the A defect concentration in diamond

Abstract The nitrogen concentrations of a suite of thirteen purely type IaA diamonds have been determined by a destructive method involving combustion of the specimens and measurement, by capacitance manometry, of the released nitrogen. These values have been related to measurements of the infrared absorption strength due to nitrogen in the form of A centres, or nitrogen-pair defects, in the specimens. It is found that an absorption coefficient of 1 cm−1, at 1282 wavenumbers, is produced by 16.1 ± 1 at. p.p.m. of nitrogen in this form. This is in good agreement with the values found by inert-gas fusion and by an indirect method described in the previous paper. Application of a statistical analysis to these three consistent sets of results taken collectively suggests that a reliable working value for the absorption strength at 1282 wavenumbers due to the A defect in diamond would be 1cm−1 per 16.5 ±1 at. p.p.m.