Systems of Luminescence in Diamond at 489 nm

A zero-phonon line at 488.9 nm (2.53 eV) is observed in the photoluminescence spectra of natural Ia type diamond crystals. The excitation spectrum of the system mirrors the emission spectrum. The 488.9 nm line has phonon repetitions corresponding to an energy of 0.073 eV. Changing the temperature from 77 to 313 K shifts the position of the system by 1.01 nm toward the red region; the drop in intensity and broadening of the full width at half maximum is nonlinear. The characteristics of electron–phonon interaction and the distribution of defects with a zero-phonon line at 488.9 nm in the volume of crystals are similar to the characteristics of defects of a nitrogen–vacancy nature.