Breitman Mónica, Ruiz-Moreno Sergio, Gil Alejandro López
Department of Applied Mathematics IV, ETSETB Polytechnical University of Catalonia, Módulo C3, Campus Nord c/Jordi Girona 1-3, 08034 Barcelona, Spain.
Spectrochim Acta A Mol Biomol Spectrosc. 2007 Dec 15;68(4):1114-9. doi: 10.1016/j.saa.2007.06.042. Epub 2007 Aug 1.
Raman spectroscopy provides useful information to detect and identify pictorial materials in artworks, although some problems are involved when the identification of individual pigments in mixtures is treated. With the hypothesis of the Principle of superposition, the mixture spectrum should be the direct sum of each pondered individual spectrum. In this work, we will show several mixtures where it can be noticed that the mixture spectrum is not qualitatively proportional to the sum of pondered individual spectra. Also there were some cases where the bands of one of the pigments could not be detected in the mixture spectrum. This non-linear behaviour could be attributed to specific proprieties of each material that are revealed when they interact with each other. We conjecture that, for instance, the different reflectances or the wavelength of the laser source could be determinant factors of the obtained results. In this paper an experimental method has been designed in order to characterize the quantitative behaviour of the Raman bands corresponding to each pigment in a mixture. Adequate coefficients are defined and calculated to facilitate the study of the spectral contribution of the different components of a mixture.
拉曼光谱法为检测和识别艺术品中的绘画材料提供了有用信息，不过在处理混合物中单个颜料的识别时会涉及一些问题。基于叠加原理的假设，混合物光谱应是每个加权后的单个光谱的直接叠加。在这项工作中，我们将展示几种混合物，从中可以注意到混合物光谱与加权后的单个光谱之和在性质上不成正比。此外，在某些情况下，混合物光谱中无法检测到其中一种颜料的谱带。这种非线性行为可能归因于每种材料在相互作用时所展现出的特定性质。我们推测，例如，不同的反射率或激光源的波长可能是所得结果的决定性因素。本文设计了一种实验方法，以表征混合物中对应于每种颜料的拉曼谱带的定量行为。定义并计算了适当的系数，以促进对混合物不同成分光谱贡献的研究。
