Arianna Passaretti, Luana Cuvillier, Claude-Alain Künzi, Laura Brambilla, Edith Joseph
Jean Dunand (1877–1942) was a European artist internationally appreciated at his time for his innovative Art Déco housewares made of hammer-beaten copper-based alloys, known as dinanderie. Still uncertain was the nature of the constituting materials; therefore, for the first time, three objects, namely, a bowl, a trinket bowl and a vase, were the target of a multi-modal work of characterisation. Mobile or benchtop X-ray fluorescence, Fourier-transform infrared (FTIR) and Raman spectroscopies were used to adapt the analyses to the shape and size of the artefacts. Elemental analysis verified that the vase consisted of brass Cu70Zn30, whereas the bowl and the trinket bowl were made of nickel silver Cu70Zn19Ni11. The black finishing present on all the artefacts was related to tenorite by Raman spectroscopy, ascribing the patina to an intentional artist's willing and not to spontaneous tarnishing processes. Metal soaps of copper and zinc were documented as degradation products by FTIR spectroscopy. The drawings adorning the vase and the trinket bowl were identified as silver-based, contrary to what was hypothesised by conservators (i.e., tin-based) due to conventional Dunand's inlaying technique. Besides single-point analysis, Raman mapping was performed in-situ, applying for the first time a Virsa™ Raman Analyser (Renishaw) in the field of cultural heritage. The fibre-optic-coupled instrument allowed to comply constantly with the artefacts' geometry thanks to the modular probe and the motorised focus-tracking stand. The synergic combination of elemental and vibrational analyses resulted successful, providing new and unique information on artist's technique in view of possible restoration interventions.
{"title":"Multi-analytical characterisation of Art Déco dinanderie: Single-point and map analysis of Jean Dunand's metal artworks","authors":"Arianna Passaretti, Luana Cuvillier, Claude-Alain Künzi, Laura Brambilla, Edith Joseph","doi":"10.1002/jrs.6712","DOIUrl":"10.1002/jrs.6712","url":null,"abstract":"<p>Jean Dunand (1877–1942) was a European artist internationally appreciated at his time for his innovative Art Déco housewares made of hammer-beaten copper-based alloys, known as <i>dinanderie</i>. Still uncertain was the nature of the constituting materials; therefore, for the first time, three objects, namely, a bowl, a trinket bowl and a vase, were the target of a multi-modal work of characterisation. Mobile or benchtop X-ray fluorescence, Fourier-transform infrared (FTIR) and Raman spectroscopies were used to adapt the analyses to the shape and size of the artefacts. Elemental analysis verified that the vase consisted of brass Cu<sub>70</sub>Zn<sub>30</sub>, whereas the bowl and the trinket bowl were made of nickel silver Cu<sub>70</sub>Zn<sub>19</sub>Ni<sub>11</sub>. The black finishing present on all the artefacts was related to tenorite by Raman spectroscopy, ascribing the patina to an intentional artist's willing and not to spontaneous tarnishing processes. Metal soaps of copper and zinc were documented as degradation products by FTIR spectroscopy. The drawings adorning the vase and the trinket bowl were identified as silver-based, contrary to what was hypothesised by conservators (i.e., tin-based) due to conventional Dunand's inlaying technique. Besides single-point analysis, Raman mapping was performed in-situ, applying for the first time a Virsa™ Raman Analyser (Renishaw) in the field of cultural heritage. The fibre-optic-coupled instrument allowed to comply constantly with the artefacts' geometry thanks to the modular probe and the motorised focus-tracking stand. The synergic combination of elemental and vibrational analyses resulted successful, providing new and unique information on artist's technique in view of possible restoration interventions.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 12","pages":"1289-1299"},"PeriodicalIF":2.4,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6712","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141550862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Raman spectra of ferrocene crystals were measured at pressures up to 20 GPa, and an abnormally large bandwidth of intermolecular phonons at ambient pressure was found. With an increase in the pressure, the bandwidth increased to a maximum at ~2 GPa and then decreased to a minimum at ~4 GPa, which was equal to the pressure-independent bandwidth of intramolecular phonons. The unusual behavior of the bandwidth was related to the instability of a ferrocene molecule caused by jumps between its D5d and D5h conformations. A decrease in the time of jumps between the conformations to the period of crystal lattice vibrations led to a loss of coherence and broadening of intermolecular phonon bands. The energy barrier between the conformations was determined to be ~17.6 meV/molecule under ambient conditions and 80 meV/molecule at 4.9 GPa. An increase in the barrier with pressure was due to the enhancement of the crystal field, which resulted in the inhibition of the jumps and the stabilization of the molecule in the D5d conformation.
{"title":"Raman study of the conformational instability of a ferrocene molecule at high pressure: Influence of a crystal field","authors":"Konstantin Meletov","doi":"10.1002/jrs.6713","DOIUrl":"10.1002/jrs.6713","url":null,"abstract":"<p>The Raman spectra of ferrocene crystals were measured at pressures up to 20 GPa, and an abnormally large bandwidth of intermolecular phonons at ambient pressure was found. With an increase in the pressure, the bandwidth increased to a maximum at ~2 GPa and then decreased to a minimum at ~4 GPa, which was equal to the pressure-independent bandwidth of intramolecular phonons. The unusual behavior of the bandwidth was related to the instability of a ferrocene molecule caused by jumps between its D<sub>5d</sub> and D<sub>5h</sub> conformations. A decrease in the time of jumps between the conformations to the period of crystal lattice vibrations led to a loss of coherence and broadening of intermolecular phonon bands. The energy barrier between the conformations was determined to be ~17.6 meV/molecule under ambient conditions and 80 meV/molecule at 4.9 GPa. An increase in the barrier with pressure was due to the enhancement of the crystal field, which resulted in the inhibition of the jumps and the stabilization of the molecule in the D<sub>5d</sub> conformation.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 10","pages":"1105-1112"},"PeriodicalIF":2.4,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Macro-Raman mapping is an approach that is well suited to study the distribution of molecules over a surface of typically several cm2, such as the pigment distribution on a painting. During such an experiment, thousands Raman spectra are recorded in a predefined array of points. As there can be a huge difference in Raman sensitivity between different molecules, an alternative approach is proposed, where measurement times are adapted according to the quality of the Raman scatterer. Therefore, an iterative process is implemented, involving recording short accumulations, followed by a quick evaluation. As soon as the accumulated spectrum reaches a quality criterium, measurement of the next point is started, while in the other case further accumulations are added. The influence of using multiple accumulations opposite to a single measurement for a prolonged period has been assessed by comparing the overall measurement time and the spectral intensity of the main Raman band (520.5 cm−1) of silicon. Another prerequisite for this algorithm to be successful is the need for a quick and reliable evaluation of the spectral quality. This was examined by applying this function on the accumulations of Raman spectra of 49 paint samples from a colour chart. Finally, the variable-accumulation algorithm is applied during a macro-Raman mapping experiment of a watercolour painting on paper. Despite a significant gain in overall measuring time, this novel approach yields a qualitative data set that can be used for creating clear Raman maps, using different data processing methods.
{"title":"An alternative macro-Raman mapping algorithm, adapting the numbers of accumulations","authors":"Peter Vandenabeele","doi":"10.1002/jrs.6715","DOIUrl":"10.1002/jrs.6715","url":null,"abstract":"<p>Macro-Raman mapping is an approach that is well suited to study the distribution of molecules over a surface of typically several cm<sup>2</sup>, such as the pigment distribution on a painting. During such an experiment, thousands Raman spectra are recorded in a predefined array of points. As there can be a huge difference in Raman sensitivity between different molecules, an alternative approach is proposed, where measurement times are adapted according to the quality of the Raman scatterer. Therefore, an iterative process is implemented, involving recording short accumulations, followed by a quick evaluation. As soon as the accumulated spectrum reaches a quality criterium, measurement of the next point is started, while in the other case further accumulations are added. The influence of using multiple accumulations opposite to a single measurement for a prolonged period has been assessed by comparing the overall measurement time and the spectral intensity of the main Raman band (520.5 cm<sup>−1</sup>) of silicon. Another prerequisite for this algorithm to be successful is the need for a quick and reliable evaluation of the spectral quality. This was examined by applying this function on the accumulations of Raman spectra of 49 paint samples from a colour chart. Finally, the variable-accumulation algorithm is applied during a macro-Raman mapping experiment of a watercolour painting on paper. Despite a significant gain in overall measuring time, this novel approach yields a qualitative data set that can be used for creating clear Raman maps, using different data processing methods.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 10","pages":"1067-1079"},"PeriodicalIF":2.4,"publicationDate":"2024-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ana de Dios-Cubillas, Olga Prieto-Ballesteros, Manfred Nachtnebel, Harald Fitzek, Hartmuth Schröttner
There is evidence from the near-infrared observations of space missions of the presence of carbonates on the surface of several ocean worlds. However, their genesis remains unresolved. We investigate the hypothesis that these carbonates may be in the form of clathrites assuming that clathrate hydrates are stable phases in the crust and ocean of these ocean worlds. In order to support this, we studied a sample of a potential clathrite from the Hydrate Ridge cold seep (Cascadia Subduction Zone), the carbonate rock fossil of clathrate hydrates, as a terrestrial analogue. We characterised the mineralogy and texture of the sample by using a coupled confocal Raman microscope and scanning electron microscopy instrument with the aim of identifying possible geo- and biosignatures, which could be relevant for future missions of exploration to ocean worlds and Mars. Our results show that aragonite is the dominant mineral phase in the clathrite sample, but Mg-calcite and dolomite were also identified. These three carbonates constitute a pattern related to clathrate hydrate formation and dissociation processes. Dolomite was defined as a biosignature of gas hydrate microbiomes because it was integrated within Mg-calcite grains precipitated after clathrate hydrate dissociation. Nevertheless, no spectral changes were observed in Raman bands of carbonate minerals that would indicate the influence of clathrate hydrates in their genesis. We also observed that Raman band positions of the associated framboidal pyrites are a characteristic signature of the associated framboid-like texture because its potential as biosignature may only be attributed by biochemical analysis.
{"title":"SEM/Raman spectroscopy of clathrites as analogs of authigenic carbonates in ocean worlds","authors":"Ana de Dios-Cubillas, Olga Prieto-Ballesteros, Manfred Nachtnebel, Harald Fitzek, Hartmuth Schröttner","doi":"10.1002/jrs.6711","DOIUrl":"10.1002/jrs.6711","url":null,"abstract":"<p>There is evidence from the near-infrared observations of space missions of the presence of carbonates on the surface of several ocean worlds. However, their genesis remains unresolved. We investigate the hypothesis that these carbonates may be in the form of clathrites assuming that clathrate hydrates are stable phases in the crust and ocean of these ocean worlds. In order to support this, we studied a sample of a potential clathrite from the Hydrate Ridge cold seep (Cascadia Subduction Zone), the carbonate rock fossil of clathrate hydrates, as a terrestrial analogue. We characterised the mineralogy and texture of the sample by using a coupled confocal Raman microscope and scanning electron microscopy instrument with the aim of identifying possible geo- and biosignatures, which could be relevant for future missions of exploration to ocean worlds and Mars. Our results show that aragonite is the dominant mineral phase in the clathrite sample, but Mg-calcite and dolomite were also identified. These three carbonates constitute a pattern related to clathrate hydrate formation and dissociation processes. Dolomite was defined as a biosignature of gas hydrate microbiomes because it was integrated within Mg-calcite grains precipitated after clathrate hydrate dissociation. Nevertheless, no spectral changes were observed in Raman bands of carbonate minerals that would indicate the influence of clathrate hydrates in their genesis. We also observed that Raman band positions of the associated framboidal pyrites are a characteristic signature of the associated framboid-like texture because its potential as biosignature may only be attributed by biochemical analysis.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 10","pages":"1057-1066"},"PeriodicalIF":2.4,"publicationDate":"2024-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6711","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yangshao culture, as the most important Neolithic culture in China, is famous for its finely decorated pottery. In this work, Yangshao potteries excavated in Shanxi province, one of the core distribution areas, were studied by micro-Raman spectroscopy combined with optical microscopy, X-ray fluorescence, and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy. The color of the red decor is derived from hematite and maghemite. The black decorations on the surface are more complex, which could be divided into two types according to the Mn/Fe ratios and crystalline types: (1) low MnO2/Fe2O3 ratio and jacobsite and magnetite and (2) high MnO2/Fe2O3 ratio and hausmannite. The former color is obviously brighter than the latter. This study also demonstrates the potential of micro-Raman microscopy in analyzing the nature of colorant crystals in Yangshao painted potteries and, therefore, better deciphering the technical details involved in the potteries of Yangshao culture.
仰韶文化是中国最重要的新石器时代文化,以其装饰精美的陶器而闻名于世。本研究采用显微拉曼光谱结合光学显微镜、X 射线荧光和配备能量色散 X 射线光谱仪的扫描电子显微镜对核心分布区之一山西省出土的仰韶彩陶进行了研究。红色装饰物的颜色来源于赤铁矿和磁铁矿。表面的黑色纹饰更为复杂,根据锰/铁比率和结晶类型可分为两类:(1) 低 MnO2/Fe2O3 比率及黝帘石和磁铁矿;(2) 高 MnO2/Fe2O3 比率及豪氏金刚石。前者的颜色明显比后者鲜艳。这项研究还证明了显微拉曼显微镜在分析仰韶彩陶中着色剂晶体性质方面的潜力,从而更好地解读仰韶文化彩陶的技术细节。
{"title":"Micro-Raman study of black and red decorations of Neolithic Yangshao potteries excavated from Taiyuan city, Shanxi province, China (c. 3000 BCE)","authors":"Ying Wang, Yuanqing Yang, Liangliang Hou, Rui Guo, Fen Wang, Jianfeng Zhu, Jingrong Pei, Hongjie Luo, Tian Wang","doi":"10.1002/jrs.6714","DOIUrl":"10.1002/jrs.6714","url":null,"abstract":"<p>Yangshao culture, as the most important Neolithic culture in China, is famous for its finely decorated pottery. In this work, Yangshao potteries excavated in Shanxi province, one of the core distribution areas, were studied by micro-Raman spectroscopy combined with optical microscopy, X-ray fluorescence, and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy. The color of the red decor is derived from hematite and maghemite. The black decorations on the surface are more complex, which could be divided into two types according to the Mn/Fe ratios and crystalline types: (1) low MnO<sub>2</sub>/Fe<sub>2</sub>O<sub>3</sub> ratio and jacobsite and magnetite and (2) high MnO<sub>2</sub>/Fe<sub>2</sub>O<sub>3</sub> ratio and hausmannite. The former color is obviously brighter than the latter. This study also demonstrates the potential of micro-Raman microscopy in analyzing the nature of colorant crystals in Yangshao painted potteries and, therefore, better deciphering the technical details involved in the potteries of Yangshao culture.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 12","pages":"1333-1340"},"PeriodicalIF":2.4,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sahroz Khan, Yana Fedortchouk, Monika Feichter, Tivadar M. Toth
Melt inclusions trapped in minerals inside xenoliths from kimberlites can help to examine the composition of kimberlite melt and/or metasomatic processes in the subcratonic lithospheric mantle as well as shed more light on the role of these melts in diamond destruction. In this study, confocal Raman spectroscopy of secondary melt inclusions in olivine from xenoliths in five different Kaapvaal Craton kimberlites was used for testing any compositional differences between melt inclusions from economically productive (Bultfontein and Frank Smit) and uneconomic diamond barren (Matsoku, Thaba Putsoa, and Pipe 200) kimberlite pipes. The xenoliths represent a range of pressures (37–45 kbar) and temperatures (1000–1300°C). The 26 daughter minerals identified within melt inclusions include Ca–Mg (±Na, K, P, Cl)-bearing carbonates, alkali (±Ca, Ba, Cl, F, H2O, CO2)-bearing sulfates, phosphates, oxides, silicates, and a rare nitrate. The mineral assemblages in melt inclusions are similar in both economic and barren kimberlite pipes from the interior and the edge of the craton, indicating the similar composition of the entrapped melts in all studied samples. However, the petrographic study revealed different metasomatic processes recorded by xenoliths from barren and economic kimberlites. Metasomatism by a melt enriched in K, Ca, and H2O could be instrumental in diamond destruction and the low diamond grade of the three barren kimberlites from Lesotho. Our study revealed no effect of kimberlite melt composition on diamond preservation in the studied kimberlites: instead, diamond grade is most likely affected by diamond destruction in the mantle source prior to kimberlite emplacement with kimberlite ascent.
{"title":"Confocal Raman spectroscopic study of melt inclusions from peridotite xenoliths in economic and barren kimberlites from Kaapvaal Craton","authors":"Sahroz Khan, Yana Fedortchouk, Monika Feichter, Tivadar M. Toth","doi":"10.1002/jrs.6709","DOIUrl":"https://doi.org/10.1002/jrs.6709","url":null,"abstract":"<p>Melt inclusions trapped in minerals inside xenoliths from kimberlites can help to examine the composition of kimberlite melt and/or metasomatic processes in the subcratonic lithospheric mantle as well as shed more light on the role of these melts in diamond destruction. In this study, confocal Raman spectroscopy of secondary melt inclusions in olivine from xenoliths in five different Kaapvaal Craton kimberlites was used for testing any compositional differences between melt inclusions from economically productive (Bultfontein and Frank Smit) and uneconomic diamond barren (Matsoku, Thaba Putsoa, and Pipe 200) kimberlite pipes. The xenoliths represent a range of pressures (37–45 kbar) and temperatures (1000–1300°C). The 26 daughter minerals identified within melt inclusions include Ca–Mg (±Na, K, P, Cl)-bearing carbonates, alkali (±Ca, Ba, Cl, F, H<sub>2</sub>O, CO<sub>2</sub>)-bearing sulfates, phosphates, oxides, silicates, and a rare nitrate. The mineral assemblages in melt inclusions are similar in both economic and barren kimberlite pipes from the interior and the edge of the craton, indicating the similar composition of the entrapped melts in all studied samples. However, the petrographic study revealed different metasomatic processes recorded by xenoliths from barren and economic kimberlites. Metasomatism by a melt enriched in K, Ca, and H<sub>2</sub>O could be instrumental in diamond destruction and the low diamond grade of the three barren kimberlites from Lesotho. Our study revealed no effect of kimberlite melt composition on diamond preservation in the studied kimberlites: instead, diamond grade is most likely affected by diamond destruction in the mantle source prior to kimberlite emplacement with kimberlite ascent.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 10","pages":"1090-1104"},"PeriodicalIF":2.4,"publicationDate":"2024-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6709","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ilaria Costantini, Julene Aramendia, Idoia Etxebarria, Iñaki Vazquez de la Fuente, Kepa Castro, Iban Sanchez-Pinto, Lucía Pérez, Beatriz Yécora, Macarena Sanz, Nagore Prieto-Taboada, Ander de la Fuente, Irantzu Martinez-Arkarazo, Agustin Azkarate, Ángel Yedra, Tamara Oroz, Gorka Arana, Juan Manuel Madariaga
This work describes the diagnostic study on the building materials, mostly carbonated, belonging to Santa Maria Cathedral and the Medieval Wall of Vitoria-Gasteiz (Spain) with the aim to design the best conservation procedure. Both the studies of the lithology and the secondary compounds originated by environmental impacts on the Cathedral and on the Medieval Wall were carried out using laboratory instruments (μ-Raman and micro-energy-dispersive X-ray spectroscopy, X-ray diffraction and ion chromatography) on selected samples provided by the restorers. The systematic presence of black crusts in the stones of the Cathedral was related to the growth of microcrystalline structures of secondary compounds and biological patinas and the deposition of atmospheric particles from traffic and house heating systems. In fact, the main components identified were carbon, and iron compounds such as hematite, goethite, magnetite and lepidocrocite. In addition, the detection of lead compounds (lead-rich hydroxyapatite) suggested in the same way the impact of the urban environment on the degradation and blackening of stone materials. The presence of sulfates, mainly gypsum, and, to a lesser extent, epsomite, anhydrite and bloedite could be caused by the sulfation of carbonated compounds as a result of an acid attack of atmospheric pollutants. The results on the secondary products of the Medieval Wall showed a greater presence of degradation by microorganisms compared to the Cathedral. This is probably related to the large garden surrounding the fortification, where the grass is in direct contact to the lower part of the structure. Markers of biological activity, such as carotenoid pigments and calcium oxalate weddellite, together with other soluble oxalates were identified. The presence of ammonium nitrate, characterised by means ion chromatography, causes a chemical degradation of carbonate stone materials over time, due to the acidic nature of the ammonium ion. In both cases considered in this study, the presence of nitrate compounds, nitratine and potassium nitrate, was attributed to both natural factors (ammonium nitrate is coming from the decomposition of plant and animal excretions), and anthropogenic contamination.
{"title":"Raman spectroscopy assisted by other analytical techniques to identify the most deteriorated carbonate-stones to be consolidated in two monuments of Vitoria-Gasteiz (Spain)","authors":"Ilaria Costantini, Julene Aramendia, Idoia Etxebarria, Iñaki Vazquez de la Fuente, Kepa Castro, Iban Sanchez-Pinto, Lucía Pérez, Beatriz Yécora, Macarena Sanz, Nagore Prieto-Taboada, Ander de la Fuente, Irantzu Martinez-Arkarazo, Agustin Azkarate, Ángel Yedra, Tamara Oroz, Gorka Arana, Juan Manuel Madariaga","doi":"10.1002/jrs.6710","DOIUrl":"https://doi.org/10.1002/jrs.6710","url":null,"abstract":"<p>This work describes the diagnostic study on the building materials, mostly carbonated, belonging to Santa Maria Cathedral and the Medieval Wall of Vitoria-Gasteiz (Spain) with the aim to design the best conservation procedure. Both the studies of the lithology and the secondary compounds originated by environmental impacts on the Cathedral and on the Medieval Wall were carried out using laboratory instruments (μ-Raman and micro-energy-dispersive X-ray spectroscopy, X-ray diffraction and ion chromatography) on selected samples provided by the restorers. The systematic presence of black crusts in the stones of the Cathedral was related to the growth of microcrystalline structures of secondary compounds and biological patinas and the deposition of atmospheric particles from traffic and house heating systems. In fact, the main components identified were carbon, and iron compounds such as hematite, goethite, magnetite and lepidocrocite. In addition, the detection of lead compounds (lead-rich hydroxyapatite) suggested in the same way the impact of the urban environment on the degradation and blackening of stone materials. The presence of sulfates, mainly gypsum, and, to a lesser extent, epsomite, anhydrite and bloedite could be caused by the sulfation of carbonated compounds as a result of an acid attack of atmospheric pollutants. The results on the secondary products of the Medieval Wall showed a greater presence of degradation by microorganisms compared to the Cathedral. This is probably related to the large garden surrounding the fortification, where the grass is in direct contact to the lower part of the structure. Markers of biological activity, such as carotenoid pigments and calcium oxalate weddellite, together with other soluble oxalates were identified. The presence of ammonium nitrate, characterised by means ion chromatography, causes a chemical degradation of carbonate stone materials over time, due to the acidic nature of the ammonium ion. In both cases considered in this study, the presence of nitrate compounds, nitratine and potassium nitrate, was attributed to both natural factors (ammonium nitrate is coming from the decomposition of plant and animal excretions), and anthropogenic contamination.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 12","pages":"1309-1321"},"PeriodicalIF":2.4,"publicationDate":"2024-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6710","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142851442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Attempting to compute the excess Raman spectra, the authors found that the method of spectral normalization greatly influences not only the intensity but also the shape of the excess spectra. We here present a method for the computation of normalized excess Raman spectra that is regarded as thermodynamically consistent. In the presented method, the normalized excess Raman spectra are computed from molar Raman spectra, which cannot be measured directly. It is therefore described how they can be obtained from intensity-normalized Raman spectra and a regression of mixture Raman spectra.
{"title":"Thermodynamically consistent derivation of excess Raman spectra","authors":"Miriam Willger, Andreas Siegfried Braeuer","doi":"10.1002/jrs.6707","DOIUrl":"10.1002/jrs.6707","url":null,"abstract":"<p>Attempting to compute the excess Raman spectra, the authors found that the method of spectral normalization greatly influences not only the intensity but also the shape of the excess spectra. We here present a method for the computation of normalized excess Raman spectra that is regarded as thermodynamically consistent. In the presented method, the normalized excess Raman spectra are computed from molar Raman spectra, which cannot be measured directly. It is therefore described how they can be obtained from intensity-normalized Raman spectra and a regression of mixture Raman spectra.</p>","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":"55 10","pages":"1080-1089"},"PeriodicalIF":2.4,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jrs.6707","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141376270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}