Luminescence decay time of the 1.945 eV centre in type Ib diamond

The luminescence decay time of the 1.945 eV centre has been determined as 13+or-0.5 ns for natural type Ib diamonds. For synthetic diamonds the value is slightly lower, probably because of competitive non-radiative recombination in these relatively impure crystals. The similarity of the decay time to that for the H3 centre further supports the model proposed for the vacancy-enhanced aggregation of nitrogen in diamond. No temperature dependence of the 1.945 eV decay time has been detected in the range 77-700K, and this result is not inconsistent with the energy level scheme used to interpret ESR data for the 1.945 eV centre.