The form of different charge states of the vacancy in diamond

There are many different centres formed in diamond that have similar optical characteristics such as a sharp zero phonon line and phonon sidebands. Electronic structure and behaviour of some of these defects is analysed in terms of an intrinsic lattice vacancy model. Using such a model (which sometimes provides a clearer interpretation of experimental results) a comparison of stress matrix elements for the GR1, ND1, H3, N3 and 1,945 eV centres is made. It is concluded that the main behaviour of these defects can simply be associated with the different charged states V⁰, V^?, V^2? and V^3?—the role of nitrogen (apart from providing electrons) being to lower the symmetry about the vacancy.