The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra... more The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra Sigillata sample wares. The broadening of the Raman lines and the appearance and increasing of the disorder band at 660 cm(-1), while moving from the external slip to the inner body, are proposed as valuation parameters for the study of the mineralogical composition and firing process of pottery productions.
This work explores the application of chemometric techniques to the analysis of lipidic paint bin... more This work explores the application of chemometric techniques to the analysis of lipidic paint binders (i.e., drying oils) by means of Raman and near-infrared spectroscopy. These binders have been widely used by artists throughout history, both individually and in mixtures. We prepared various model samples of the pure binders (linseed, poppy seed, and walnut oils) obtained from different manufacturers. These model samples were left to dry and then characterized by Raman and reflectance near-infrared spectroscopy. Multivariate analysis was performed by applying principal component analysis (PCA) on the first derivative of the corresponding Raman spectra (1800-750 cm(-1)), near-infrared spectra (6000-3900 cm(-1)), and their combination to test whether spectral differences could enable samples to be distinguished on the basis of their composition. The vibrational bands we found most useful to discriminate between the different products we studied are the fundamental v(C=C) stretching a...
Micro-Raman spectroscopy has been widely applied to the investigation of heterogeneous materials ... more Micro-Raman spectroscopy has been widely applied to the investigation of heterogeneous materials for it enables a not destructive way for the microscopic identification of the various chemical components. However it may not ever answer the question of how these species are distributed on a specific area. Global Raman imaging represents in this sense the ideal solution, for it combines Raman spectroscopy and digital imaging to provide molecular images that detail material morphology, composition and structure. By filtering a given Raman band over a wide sample area, the correspondent intensity distribution is immediately constructed in a bidimensional map which allows the user to easily and visually determine the location of even complex components in the irradiated sample area. An example of how a distribution map may be obtained by global Raman imaging is here reported for a fresco cross-sectioned sample.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
The analysis of ground state structural and vibrational properties of Safranin-O is presented. Th... more The analysis of ground state structural and vibrational properties of Safranin-O is presented. The experimental results, obtained by FTIR, Raman and SERS spectroscopy, are discussed in comparison to the results of DFT calculations carried out at the B3LYP/6-311+G(d,p) level of theory. The calculated spectra reproduce quite satisfactorily the experimental data. The calculated Safranin-O equilibrium structure and the assignment of the vibrational spectra are reported as well. From the changes between Raman and SERS spectra a model is presented for the interaction of Safranin-O with silver nanoparticles.
The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra... more The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra Sigillata sample wares. The broadening of the Raman lines and the appearance and increasing of the disorder band at 660 cm(-1), while moving from the external slip to the inner body, are proposed as valuation parameters for the study of the mineralogical composition and firing process of pottery productions.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2009
Five polychrome prints representing famous painters, such as Albrecht Dürer, were analyzed using ... more Five polychrome prints representing famous painters, such as Albrecht Dürer, were analyzed using a non-destructive and non-invasive methodology as required by the artwork typology. The diagnostic strategy includes X-ray fluorescence (XRF), reflectance micro-infrared (microFTIR) and micro-Raman (microRaman) spectroscopy. These prints were realized with a la poupée method that involves application of the polychrome inks on a single copper plate, before the printing process. A broad range of compounds (i.e., cinnabar, red lead, white lead, umber earth, hydrated calcium sulfate, calcium carbonate, amorphous carbon, and Prussian blue) was employed as chalcographic inks, using linseed oil as a binding medium. Gamboge was identified in the delicate finishing brush touches realized in watercolor.
The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra... more The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra Sigillata sample wares. The broadening of the Raman lines and the appearance and increasing of the disorder band at 660 cm(-1), while moving from the external slip to the inner body, are proposed as valuation parameters for the study of the mineralogical composition and firing process of pottery productions.
This work explores the application of chemometric techniques to the analysis of lipidic paint bin... more This work explores the application of chemometric techniques to the analysis of lipidic paint binders (i.e., drying oils) by means of Raman and near-infrared spectroscopy. These binders have been widely used by artists throughout history, both individually and in mixtures. We prepared various model samples of the pure binders (linseed, poppy seed, and walnut oils) obtained from different manufacturers. These model samples were left to dry and then characterized by Raman and reflectance near-infrared spectroscopy. Multivariate analysis was performed by applying principal component analysis (PCA) on the first derivative of the corresponding Raman spectra (1800-750 cm(-1)), near-infrared spectra (6000-3900 cm(-1)), and their combination to test whether spectral differences could enable samples to be distinguished on the basis of their composition. The vibrational bands we found most useful to discriminate between the different products we studied are the fundamental v(C=C) stretching a...
Micro-Raman spectroscopy has been widely applied to the investigation of heterogeneous materials ... more Micro-Raman spectroscopy has been widely applied to the investigation of heterogeneous materials for it enables a not destructive way for the microscopic identification of the various chemical components. However it may not ever answer the question of how these species are distributed on a specific area. Global Raman imaging represents in this sense the ideal solution, for it combines Raman spectroscopy and digital imaging to provide molecular images that detail material morphology, composition and structure. By filtering a given Raman band over a wide sample area, the correspondent intensity distribution is immediately constructed in a bidimensional map which allows the user to easily and visually determine the location of even complex components in the irradiated sample area. An example of how a distribution map may be obtained by global Raman imaging is here reported for a fresco cross-sectioned sample.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
The analysis of ground state structural and vibrational properties of Safranin-O is presented. Th... more The analysis of ground state structural and vibrational properties of Safranin-O is presented. The experimental results, obtained by FTIR, Raman and SERS spectroscopy, are discussed in comparison to the results of DFT calculations carried out at the B3LYP/6-311+G(d,p) level of theory. The calculated spectra reproduce quite satisfactorily the experimental data. The calculated Safranin-O equilibrium structure and the assignment of the vibrational spectra are reported as well. From the changes between Raman and SERS spectra a model is presented for the interaction of Safranin-O with silver nanoparticles.
The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra... more The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra Sigillata sample wares. The broadening of the Raman lines and the appearance and increasing of the disorder band at 660 cm(-1), while moving from the external slip to the inner body, are proposed as valuation parameters for the study of the mineralogical composition and firing process of pottery productions.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2009
Five polychrome prints representing famous painters, such as Albrecht Dürer, were analyzed using ... more Five polychrome prints representing famous painters, such as Albrecht Dürer, were analyzed using a non-destructive and non-invasive methodology as required by the artwork typology. The diagnostic strategy includes X-ray fluorescence (XRF), reflectance micro-infrared (microFTIR) and micro-Raman (microRaman) spectroscopy. These prints were realized with a la poupée method that involves application of the polychrome inks on a single copper plate, before the printing process. A broad range of compounds (i.e., cinnabar, red lead, white lead, umber earth, hydrated calcium sulfate, calcium carbonate, amorphous carbon, and Prussian blue) was employed as chalcographic inks, using linseed oil as a binding medium. Gamboge was identified in the delicate finishing brush touches realized in watercolor.
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