Calculation of linewidths of the GR2-8 transitions in diamond in a model where the energy levels are within the valence band

Linewidths of transitions between band gap states and localised energy levels within the valence band have been calculated. They show that it is possible to account for the small linewidths of the GR2-8 transitions about the vacancy in diamond provided the localised levels are very close within the valence band, but they are not consistent with Lowther's (1977) model of the GR2-8 transitions.