Spectral components that form UV absorption spectrum of Ce3+ and Ce(IV) valence states in matrix of photothermorefractive glasses

We have measured the UV absorption spectra of photothermorefractive glasses of the system Na₂O-ZnO-Al₂O₃-NaF-SiO₂ doped by cerium oxide in the range of (2.8–5.0) × 10⁴ cm⁻¹ (360–200 nm). The spectra have been processed by the method of dispersion analysis based on the analytical convolution model for the complex dielectric function of glasses. We show that the absorption band centered at 3.3 × 10⁴ cm⁻¹ (∼303 nm) that is attributed to the transition 2F _5/2 → 5d in the Ce³⁺ ion, is an envelope of three spectral components. The broad absorption range (3.5–4.7) × 10⁴ cm⁻¹ (200–270 nm) that is commonly interpreted as a charge transfer band of the Ce(IV) valence state, is an envelope of at least three spectral components.