The role of defect interactions in reducing the decay time of H3 luminescence in diamond

The decay time of the cathodoluminescence emission from the H3 centre has been measured for diamonds containing nitrogen concentrations up to 0.15 atomic per cent, the nitrogen being predominantly in the A form. In five diamonds with low nitrogen concentrations, <or approximately=0.01 atomic per cent, the mean decay time was found to be 16.7+or-0.5 ns, and this is considered to be close to the radiative lifetime of the H3 centre. For diamonds in which the width of the zero-phonon absorption line is predominantly controlled by the strain field of the A form of nitrogen, the decay time decreases linearly with the increasing width of the emission line. These results are shown to be consistent with a dipole-quadrupole transfer of energy from the H3 centres to the A form of nitrogen.