Temperature dependences of the 603/700/787 nm system photoluminescence in natural diamond

he study was carried out on temperature dependences of the 603/700/787 nm system photoluminescence in a natural diamond crystal at range from 80 to 470 K. It was found two zero phonon lines 584 nm (2,124 eV) and 603 nm (2,054 eV) are electronic transitions from sublevels of the split excited state with activation energy of 70 meV. Temperature behavior of the zero-phonon lines 656 nm (1.888 eV) and 700 nm (1.770 eV) also corresponds to the split excited state with activation energy of 118 meV.