SMAArt, Dipartimento di Chimica, Via Elce di Sotto, 8 06123 Perugia.
Appl Spectrosc. 2010 Aug;64(8):956-63. doi: 10.1366/000370210792080975.
With the aim of characterizing ground preparations of paintings by infrared reflection spectroscopy, the CaSO(4)-H(2)O system (gypsum/bassanite/anhydrite) has been re-investigated, evaluating and assigning the SO(4)(2-) and OH overtone and combination bands, respectively, in the ranges 1900-2700 cm(-1) and 5000-6000 cm(-1) resulting from reflection and high concentration transmission spectra. The second-order modes have been proven to be highly specific, reliable, and less affected by overlap with bands of organic binders and can hence be exploited for the identification of the sulfate hydration phase using infrared (IR) reflection spectroscopy. Subsequently, the characterization and identification of hydration phases in unknown sulfate-based ground preparations on authentic artworks have been carried out noninvasively by fiber-optic reflection IR spectroscopy and on cross-sections by infrared reflection micro-spectroscopy. The spectroscopic data collected both on standards and artworks have been cross-validated by X-ray diffraction.
为了通过红外反射光谱对绘画的地面准备进行特征描述，我们重新研究了 CaSO(4)-H(2)O 体系（石膏/硬石膏/无水石膏），分别评估和分配了 SO(4)(2-)和 OH 倍频和合频带，其范围分别为 1900-2700 cm(-1)和 5000-6000 cm(-1)，这是来自反射和高浓度透射光谱的结果。二阶模式被证明具有高度的特异性、可靠性，并且受有机粘合剂带的重叠影响较小，因此可以利用红外（IR）反射光谱来鉴定硫酸盐水合相。随后，通过光纤反射红外光谱对真实艺术品上未知硫酸盐基地面准备的水合相进行了非侵入性的特征描述和鉴定，并且通过红外反射微光谱对横截面进行了鉴定。在标准品和艺术品上收集的光谱数据通过 X 射线衍射进行了交叉验证。
