Analysis of the absorption spectra and spectral hole burning in zero-phonon lines of F+3 and N1 colour centres in LiF crystals

The temperature dependences and mechanisms of broadening of zero-phonon lines of F⁺₃ (488 nm) and N₁ (523 nm) colour centres in LiF crystals are investigated. The results obtained make it possible to determine the quadratic electronic—vibrational coupling constant for N₁ colour centres. The experimental data on the spectral hole burning in zero-phonon lines of F⁺₃ and N₁ colour centres indicate that the latter are positively charged.