Figure 2

Laboratory Raman spectra acquired on an apatite target after different durations of UV irradiation (0 min, 5 min, 30 min, 270 min, 1270 min), normalized to the mean signal. The plots are color coded with irradiation time. (A) Normalized spectra (x-axis shows wavenumber in cm⁻¹); (B) Close-view in the 900–1000 cm⁻¹ spectral range; baseline-corrected experimental data ( +) and fitted pseudo-Voigt profile (full lines). (C) Intensity of the \(\nu_{1}\) mode of apatite extracted from the normalized spectra (amplitude of the fitted pseudo-Voigt profile) as a function of the duration of target irradiation. The error bars represent the uncertainty values of the parameters derived from the peak fitting procedure (smaller than the markers, in this case).