Diamond possesses extreme properties: its thermal conductivity
exceeds that of copper, its thermal expansion is small,
it is the hardest natural material, it is almost completely transparent
over the visible and infrared spectral regions, and it
absorbs X-rays weakly. Impurities and defects in diamond affect
its properties as diverse as color1 and other optical properties2
and thermal conductivity;3 these properties are important in
geology, electronics, and diamond synthesis. In addition, diamond
has become much more attractive for quantum spintronics
in solid-state electronics. With the development of this technique,
its application might lead to development of a practical
quantum computer.4 The key function of diamond for quantum
spintronics is doping with a nitrogen impurity. Moreover,
diamond serves as a testing ground in solid-state physics for
theoretical calculations on point defects. It is consequently of
interest to distinguish these impurities and defects, which are
responsible for the absorption and luminescence of diamond.