OPTICAL-ABSORPTION AND LUMINESCENCE IN DIAMOND

This review outlines some relevant aspects of theoretical physics-molecular orbital and other calculation of the properties of point defects, symmetry and group theory, zero-phonon lines and the configuration coordinate diagram. The experimentally observed spectra can conveniently be divided into infrared (<1 eV), which are observed in absorption and are mainly vibrational, and 'visible' (1-5.5 eV), which are vibronic and are observed in both absorption and luminescence. 'Visible' spectra include those present naturally, those induced by irradiation, and those induced by irradiation plus annealing. This review covers all the important point defects observed optically in diamond, and includes some results which are not generally available. The relevance of the experimental results to the current controversy about how to calculate the properties of point defects is brought out.