Showing papers in "Journal of Raman Spectroscopy in 1997"
TL;DR: In this paper, the laser power dependence of the spectra of oxides and oxyhydroxides was investigated by using Raman microscopy, and it was shown that increasing laser power causes the characteristic bands of hematite to show up in the spectrum of most of the compounds studied.
Abstract: Hematite (α-Fe2O3), magnetite (Fe3O4), wustite (FeO), maghemite (γ-Fe2O3), goethite (α-FeOOH), lepidocrocite (γ-FeOOH) and δ-FeOOH were studied by Raman microscopy. Such compounds have already been studied by Raman spectroscopy, but there are some disagreements in the reported data. Here, Raman microscopy was employed to investigate the laser power dependence of the spectra of these oxides and oxyhydroxides. Low laser power was used for the reference spectra in order to minimize the risks of spectral changes due to sample degradation. The results obtained show that increasing laser power causes the characteristic bands of hematite to show up in the spectra of most of the compounds studied whereas the hematite spectrum undergoes band broadening and band shifts. © 1997 John Wiley & Sons, Ltd.
2,569 citations
TL;DR: In this article, the authors measured the unpolarized and polarized Raman spectra of LiCoO2 with a layered rock-salt structure and assigned the Raman-active lattice modes of Li-CoO 2 by measuring a c-axis oriented thin film.
Abstract: Unpolarized and polarized Raman spectra (200–800 cm-1) of LiCoO2 with a layered rock-salt structure were measured. The Raman-active lattice modes of LiCoO2 were assigned by polarized Raman measurements of a c-axis oriented thin film. The variation of the Raman spectra of Li1-xCoO2 powder prepared by electrochemical lithium deintercalation was investigated, and the spectral changes were well correlated with the structural changes determined by x-ray diffraction except that peak splitting by the distortion in the monoclinic phase was not observed. The observed line broadening of the second hexagonal phase and the monoclinic phase indicated that the lithium ions remaining in the lattice after deintercalation randomly occupy the available sites on the lithium planes in the lattice the layered rock-salt structure. © 1997 John Wiley & Sons, Ltd.
264 citations
TL;DR: In this article, near-infrared Fourier transform (NIR-FT) Raman spectroscopy was used to study the molecular alterations in the most common skin cancer, basal cell carcinoma (BCC).
Abstract: Skin cancers are the most common form of malignant neoplasms in man. In this work, near-infrared Fourier transform (NIR-FT) Raman spectroscopy was used to study the molecular alterations in the most common skin cancer, basal cell carcinoma (BCC). Biopsies from 16 histopathologically veri‐ed BCC and 16 biopsies from normal skin were harvested and analysed by NIR-FT-Raman spectroscopy using a 1064 nm Nd : YAG laser as a radiation source. Di†erences in Raman spectra between BCC and normal skin indicated alterations in protein and lipid structure in skin cancer samples. Spectral changes were observed in protein bands, amide I (1640‐1680 cm~1), amide III (1220‐1300 cm~1) and m(C‐C) streching (probably in the amino acids proline and valine, 928‐940 cm~1), and in bands characteristic of lipids, scissoring vibration (1420‐1450 cm~1) and in-phase CH 2 E(CH 2 ) n E twist vibration around 1300 cm~1. Moreover, possible changes in polysaccharide structure were found in the region 840‐860 cm~1. Analysis of the band intensities in the regions 1220‐1360, 900‐990 and 830‐900 cm~1 allowed for a complete separation between BCC and normal skin spectra. In addition to a direct assessment of spectral intensities, a neural network analysis was performed, which con‐rmed the di†erences in spectra between BCC and normal skin. In conclusion, Raman spectra from BCC di†er considerably from those of normal skin. Hence, Raman spectroscopy can be viewed as a promising tool for the diagnosis of skin cancer. 1997 by John Wiley &
207 citations
TL;DR: In this article, an in-vivo Raman system (IVRS) is described which can obtain spectra in vivo from tissue in less than 30 s. The performance of the IVRS was compared with that of an FT-Raman system.
Abstract: In recent studies, the diagnostic potential of Raman spectroscopy has been investigated. The majority of this work has been done on tissue in vitro with laboratory-based near-infrared Fourier transform (FT) Raman systems. In vivo Raman spectroscopy is hindered by tissue fluorescence, which is several orders of magnitude greater than the Raman signal, and by the spectral contribution of the delivery and collection fiber optics. An in vivo Raman system (IVRS) is described which can obtain spectra in vivo from tissue in less than 30 s. The system is compact and mobile, making it suitable for clinical applications. Major system components, such as the spectrograph, CCD detector, laser diode and fiber-optic probes, are described in detail. The methods of wavenumber calibration, intensity correction and baseline subtraction are outlined. Spectra which were collected in vivo from human skin, buccal cheek epithelium, fingernail and a tooth are presented and major peaks are assigned. The performance of the IVRS was compared with that of an FT-Raman system. With similar collection parameters, the IVRS spectra had superior signal-to-noise ratios owing to the shorter excitation wavelength (785 nm versus 1064 nm) and the high transmission (>50%) of the IVRS spectrograph. Planned system upgrades are discussed together with the anticipated improvements in system performance. © 1997 by John Wiley & Sons, Ltd.
139 citations
TL;DR: In this article, temperature dependence of the vibrational wavenumbers, of the anharmonic and/or order-disorder origin of the damping and of the Raman intensities are briefly presented.
Abstract: The temperature dependence of the vibrational wavenumbers, of the anharmonic and/or order–disorder origin of the damping and of the Raman intensities are briefly presented. On that basis, it is then shown that one can obtain information such as the height of the potential barrier, the orientational correlation time, the spatial correlation length and the anharmonic contribution to the Raman peak evolution with temperature. The concepts were applied and exploited with success in three characteristic cases, diethylenetriammonium chlorocadmate [(denH3)CdCl5] single crystals, zinc thiourea sulphate [ZTS] single crystals and lead–lanthanum zirconate–titanate [PLZT] ceramics in which order–disorder and structural phase transitions are observed. © 1997 John Wiley & Sons, Ltd.
116 citations
TL;DR: In this article, the Raman spectra of carbon nanotubes prepared by catalytic (C-CNT) and d.c. arc discharge methods are reported, and a previously unnoticed third-order Raman peak at ca. 4248 cm-1 was observed in the spectrum of D-cNT.
Abstract: The Raman spectra of carbon nanotubes prepared by catalytic (C-CNT) and d.c. arc discharge (D-CNT) methods are reported. A previously unnoticed third-order Raman peak at ca. 4248 cm-1 was observed in the Raman spectrum of D-CNT. The Raman features of D-CNT and C-CNT are similar to those of highly oriented pyrolytic graphite (HOPG) and active carbon, respectively. The data also suggest that the increase in disorder in D-CNT compared with HOPG is due to structural defects in D-CNT. © 1997 by John Wiley & Sons, Ltd.
111 citations
TL;DR: In this paper, the size determination of nanosized TiO2, by low-wavenumber Raman scattering, was also applied, which was in agreement with the crystallite sizes measured by X-ray diffraction.
Abstract: Nanosized TiO2 was prepared using the sol–gel procedure. The prepared powder was thermally treated up to 1000°C. X-ray diffraction (XRD) measurements showed that the starting powder and the samples obtained after heating this powder up to 500°C were mixtures of anatase, as the dominant phase, and brookite. The crystallite sizes of the samples were estimated using the Scherrer equation. A new approach to the size determination of nanosized TiO2, by low-wavenumber Raman scattering, was also applied. The particle sizes, determined by low-wavenumber Raman scattering, were in agreement with the crystallite sizes measured by XRD. Rutile was produced by heat treatment of the starting powder at 850°C and higher temperatures. © 1997 John Wiley & Sons Ltd.
106 citations
TL;DR: Raman spectroscopy has been used in a variety of biomedical applications including normal and diseased human tissues, single cells, implants and the presence of foreign inclusions following implantation and the interaction of certain chemical agents with tissues.
Abstract: Raman spectroscopy has been used in a variety of biomedical applications including normal and diseased human tissues, single cells, implants and the presence of foreign inclusions following implantation and the interaction of certain chemical agents with tissues. This paper surveys recent advances in biomedical Raman spectroscopy. © 1997 by John Wiley & Sons, Ltd.
98 citations
TL;DR: In this article, the Fourier transform (FT) Raman spectra of modern adult and two exfoliate (deciduous) teeth were compared with those of eight specimens of adult teeth dating from the 4th-16th centuries AD.
Abstract: An assessment is made of the applicability of Fourier transform (FT) Raman spectroscopy to the analysis of ancient human teeth from archaeological sites. Comparisons are made between the Raman spectra of nine modern adult and two exfoliate (deciduous) teeth and those of eight specimens of adult teeth dating from the 4th–16th centuries AD. From the Raman spectra of modern teeth, complete vibrational assignments are proposed for the organic proteinaceous and inorganic carbonated hydroxyapatite components. Band intensity ratio measurements of ancient teeth indicate that the collagen component does not change its conformation with burial age. Several vibrational features arising from specific amino acid residues have been identified, especially proline and hydroxyproline, representing about 10% of the total collagen. Weak bands assigned to citrate have also been assigned. For the inorganic matrix components, quantitative estimations of carbonate content have been carried out. Measurements of the relative intensities of the δ(PO) vibrations at 590 and 430 cm-1 indicate different crystalline orientations in the dental enamel and dentine hydroxyapatite components. Preliminary studies of the phenomenon of ‘pink dentine’ found in ancient teeth from certain burial environments have also been made. It is concluded that FT-Raman spectroscopy can be applied successfully to the analysis of whole ancient teeth or tooth fragments. © 1997 by John Wiley & Sons, Ltd.
93 citations
TL;DR: In this paper, the Raman bands of 1- and 2-methylimidazole were assigned to the vibrational modes based on a review of the literature assignments of imidazoles, 1-dimazole, 4(5)-methy-limidaxole supplemented by Raman depolarization studies of 1.0 and 2.
Abstract: Vibrational modes are assigned to the Raman bands of 1- and 2-methylimidazole. Assignments are based on a review of the literature assignments of imidazole, 1-methylimidazole and 4(5)-methylimidazole supplemented by Raman depolarization studies of 1.0 M solutions of 1- and 2-methylimidazole. Raman shifts observed for N-deuteration of 2-methylimidazole are also considered. © 1997 John Wiley & Sons, Ltd.
93 citations
TL;DR: In this article, a review summarizes theoretical formulations of resonance Raman scattering that express the steady-state spectrum in terms of time-dependent quantities, and a few aspects of the interpretation and practical application of these theories to real experimental data.
Abstract: This review summarizes theoretical formulations of resonance Raman scattering that express the steady-state spectrum in terms of time-dependent quantities. Time-domain expressions for the Raman or direct one-photon absorption (electronic or vibrational) lineshape are compared and contrasted with time-dependent formulations for the resonance Raman intensity. Time-domain expressions that properly describe the total spontaneous emission of a chromophore interacting with a bath are also discussed. A final section addresses a few aspects of the interpretation and practical application of these theories to real experimental data. © 1997 John Wiley & Sons, Ltd.
TL;DR: In this paper, the Raman spectra from the crustal, lichen, fungal and accumulation zones were used to assess the strategy adopted by the lichen community under environmentally stressed conditions.
Abstract: The Raman microscopic analysis of a cryptoendolithic lichen community in sandstone from East Beacon Ridge, Victoria Land, Antarctica, is described for the first time. The Raman spectra from the crustal, lichen, fungal and accumulation zones were used to assess the strategy adopted by the lichen community under environmentally stressed conditions. Calcium oxalate dihydrate was found only in the upper lichen zone, whereas calcium oxalate monohydrate was found distributed through several zones; this is ascribed to a microenvironmental temperature gradient. The leaching of iron oxide occurs from the crustal surface zone into the accumulation zone. In contradiction with earlier wet chemical destructive analyses of Antarctic cryptoendolithic communities, the presence of calcium carbonate was not confirmed in the lichen or fungal zones. The Raman spectroscopic results were confirmed by scanning electron microscopic x-ray analysis.
TL;DR: In this article, a moving spectroelectrochemical cell for surface Raman spectroscopy is described, which reduces the photodegradation of the surface-bound species and allows the use of a higher incident laser power to enhance the Raman signal.
Abstract: The construction of a moving spectroelectrochemical cell for surface Raman spectroscopy is described. Spectral distortions due to the photodegradation of the surface-bound species are reduced significantly, permitting the use of a higher incident laser power to enhance the Raman signal. The performance of the cell is demonstrated with the surface-enhanced resonance Raman spectra from the protein cytochrome P450cam (CYP101) adsorbed on a silver electrode. © 1997 by John Wiley & Sons, Ltd.
TL;DR: The Raman chirped adiabatic passage (RCAP) as mentioned in this paper is a non-resonant stimulated Raman transition for subsequent step-by-step climbing of vibrational levels.
Abstract: It is demonstrated that efficient and high vibrational excitation can be achieved using non-resonant stimulated Raman transitions for subsequent step by step climbing of vibrational levels. The pump laser (or both the pump and Stokes laser) frequency are to be swept in such a way that the frequency difference sweeping allows molecular anharmonicities of the final states to be matched. It is shown that amplitudes of successive Raman transitions can be quantitatively described with the help of the effective Raman two-level systems. This selective scheme of vibrational excitation, called Raman chirped adiabatic passage (RCAP), should be useful in controlling excited-state populations and chemical reactions. The limitations of another well known adiabatic scheme of population transfer, stimulated Raman adiabatic passage (STIRAP), are outlined and it is shown that RCAP is a complementary method to STIRAP. RCAP should be useful for selective excitation of highly polarizable symmetric bonds such as metal–metal bonds. © 1997 John Wiley & Sons, Ltd.
TL;DR: Fourier transform Raman microscopic mapping was used to examine the distribution of the mineral and organic components in a cross-section of a human tooth as discussed by the authors, and the relative distributions of carbonate and phosphate ions as well as the organic matrix components were plotted using functional group maps.
Abstract: Fourier transform Raman microscopic mapping was used to examine the distribution of the mineral and organic components in a cross-section of a human tooth. The relative distributions of carbonate and phosphate ions as well as the organic matrix components were plotted using functional group maps. The distribution of organic components was examined using the C–H stretch band between 2880 and 2700 cm-1. The distributions of phosphate and carbonate were determined using their respective symmetric stretching vibrations, νs(PO) at 961 cm-1 and νs(CO) at 1070 cm-1. Maps of the enamel–dentine junction at a high resolution of 10 μm showed that the amount of phosphate is lowest in this region. A series of spectra at 2 cm-1, ca. 20000 scans, used for curve fitting of the νs(CO) band was used to show that the concentration of carbonate ions in B-hydroxyapatite positions increases on going from the outside of the enamel towards the enamel–dentine junction. The results reveal that the deconvolution of the band envelope of νs(CO) and νas(PO), the antisymmetric stretching vibration of phosphate is more complicated than previously reported. The advantage of functional group Raman mapping is that, in addition to identifying the chemical constituents, valuable microstructural information is obtained including species distribution across the surface, and in particular at the enamel–dentine interface. Minimal, non-chemical sampling preparation means that spectral information obtained can be directly related to the physical properties and biological function of such tissues. © 1997 by John Wiley & Sons, Ltd.
TL;DR: Raman microprobe analysis of Nicalon NLM 202 and Hi-Nicalon fibres as a function of thermal treatments in various atmospheres was carried out in order to understand the fibre evolution during the synthesis of composites and their use in combustion environments.
Abstract: Raman microprobe analysis of Nicalon NLM 202 and Hi-Nicalon fibres as a function of thermal treatments in various atmospheres was carried out in order to understand the fibre evolution during the synthesis of composites and their use in combustion environments. Assignments are discussed and a description of the fibre structure on the nanoscale is proposed. A comparison is made between surface and core evolution of as-received fibres and of fibres used in the sol–gel route. The plateau observed between 1200 and 1600°C for Hi-Nicalon bands is consistent with a better thermal stability. © 1997 by John Wiley & Sons, Ltd.
TL;DR: In this paper, the distribution of DNA and proteins was investigated in bands and interbands using a linescan Raman micro-spectrometer and with a Raman imaging microscope.
Abstract: Recent results are presented of the application of imaging micro-Raman spectrometers in cellular biophysics and biomedical research. Various micro-Raman spectrometers have been developed that are now routinely applied in these fields. Results are presented that were obtained with a linescan Raman microspectrometer and with a Raman imaging microscope. Applications of Raman linescan spectrometry concern the investigation of polytene chromosomes obtained from the salivary gland of Chironomus thummi thummi. The distribution of DNA and proteins was investigated in bands and interbands. In a second example of Raman linescan spectrometry, bone implants were investigated. These bone implants were coated with thin layers of materials that improve biocompatibility. The density, crystallinity and protein distribution can be investigated. Information from Raman imaging may help in selecting the proper materials for maximum biocompatibility. Raman imaging microscopy is used whenever two-dimensional spatial information is required on the distribution of molecules or molecular components. Raman images are presented of filipine and phenylalanine in human eye-lenses in and around radial shades. Raman imaging is a particularly important tool for the study of the distribution of non-fluorescent drugs inside living cells. This is illustrated for the non-fluorescent drug cobalt octacarboxyphthalocyanine.
TL;DR: In this paper, an anomalous low-temperature behavior of Cu2O was observed by both Raman-spectroscopy using laser excitation frequencies near the resonance of the 1S "blue exciton" and x-ray powder diffractometry using a high-resolution Guinier film camera.
Abstract: Anomalous low-temperature behaviour of Cu2O is observed by both Raman-spectroscopy using laser excitation frequencies near the resonance of the 1S ‘blue exciton’ and x-ray powder diffractometry using a high-resolution Guinier film camera. Changes in frequency of the Raman-allowed Γ25+(LO) phonon band, and also of intensities of other Raman-forbidden bands, indicate anomalies at temperatures of 90 and 190 K, respectively. The anomaly at 90 K is qualitatively interpreted by an order–disorder phase transition and that at 190 K by a discontinuous change of excitonic states. Close to these temperatures, the powder diffraction diagrams also revealed anomalous behaviour of the lattice constant. Upon cooling and heating, the thermal expansion coefficient becomes significantly negative at 200 K, and at about 80 K a small reproducible contraction/expansion of the cubic lattice is observed. Both effects add evidence for hitherto unknown instabilities of the Cu2O structure at low temperatures. © 1997 John Wiley & Sons, Ltd.
TL;DR: The palettes of three Latin manuscripts (MS Lat 8, MS Lat 14 and MS Lat 17) from the collection in the D. M. S. Watson Library at University College London were analysed by Raman microscopy.
Abstract: The palettes of three Latin manuscripts (MS Lat 8, MS Lat 14 and MS Lat 17) from the collection in the D. M. S. Watson Library at University College London were analysed by Raman microscopy. The pigments vermilion (HgS), kermes (kermesic acid), azurite [2CuCO3·Cu(OH)2], malachite [CuCO3·Cu(OH)2], ivory black (a pigment based on amorphous carbon), white lead [2PbCO3·Pb(OH)2] and lead tin yellow type I (Pb2SnO4) were identified by Raman microscopy. The Raman spectra of two types of ‘mosaic gold,’ synthetic tin sulphide (SnS2), are also given, but were shown not to be present; the illuminations were obtained with gold itself. A second black pigment could not be identified. © 1997 by John Wiley & Sons, Ltd.
TL;DR: In this article, a standard, non-destructive, in situ analytical procedure has been developed to test the proposal that cinnabar [mercury(II) sulphide] is the principal component of red inks and pigments on pre-tenth century Chinese manuscripts.
Abstract: A standard, non-destructive, in situ analytical procedure has been developed to test the proposal that cinnabar [mercury(II) sulphide] is the principal component of red inks and pigments on pre-tenth century Chinese manuscripts. Eight manuscript fragments with traces of red ink or pigmentation, and also one textile fragment, were examined by Raman microscopy, Fourier transform near-infrared Raman spectroscopy and x-ray fluorescence spectroscopy. Mercury(II) sulphide was unambiguously identified on all four paper samples with red calligraphy and on the textile fragment with red pigmentation. Mercury(II) sulphide was not detected on three paper fragments with red legal or punctuation dots or on one paper fragment with a divine image hand-painted in red. The likely identity of the non-cinnabar pigment is madder. © 1997 by John Wiley & Sons, Ltd.
TL;DR: Raman spectra were obtained for a series of clinopyroxenes, orthopyroxene and inverted pigeonites from the Munni Munni layered mafic-ultramafic intrusion in Western Australia as mentioned in this paper.
Abstract: Raman spectra were obtained for a series of clinopyroxenes, orthopyroxenes and inverted pigeonites from the Munni Munni layered mafic-ultramafic intrusion in Western Australia. Their composition varies from mg48 to mg87, where mg=mg number=atomic 100 Mg/(Mg+Fe) and Fe=total Fe. The characteristic Raman bands of pyroxene are mainly due to vibrations of the SiO4 tetrahedra and occur in the 300–400, 650–700 and 980–1020 wavenumber regions of the spectra. Clinopyroxene shows only one intense Raman band in the 650–700 cm-1 region and is readily distinguished from orthorhombic pyroxene which has two intense bands in this region. This difference is probably due to the single symmetrically distinct tetrahedral site in the C2/c structure, whereas orthopyroxene has two symmetrically distinct tetrahedral chains. The pyroxenes showed systematic shifts in the wavenumber of the Raman bands with increasing mg number with the orthopyroxene spectra being the most sensitive to variations in mg number. The variations in wavenumber are believed to be related to the straightening of the tetrahedral chains and the corresponding changes in the Si—O bond lengths and O—Si—O angles caused by substitution of Fe for Mg. These changes are greater in the orthorhombic Pbca structure, because the edge-sharing polyhedra enclosing the Fe2+ and Mg2+ cations form wide bands which are separated by voids or rifts parallel to the c-axis. In the monoclinic C2/c structure, however, these polyhedra are linked in a continuous layer which restricts structural adjustments of the polyhedra and the adjacent tetrahedral SiO4 chains. Therefore, since Raman spectroscopy is sensitive to changes in crystal structure, it may be used to obtain a semi-quantitative chemical analysis of pyroxene when calibrated with a suitable solid solution series. The number of Raman bands observed and their width also gives an indication of cation order/disorder within the crystal. © 1997 Crown Copyright reserved.
TL;DR: Raman microspectroscopy has been shown to be a very powerful technique for the identification and characterization of small mineral fibres, with little or no sample preparation Such spectra are sensitive to the composition of the mineral and can often be used to distinguish between similar species.
Abstract: Raman microspectroscopy has been shown to be a very powerful technique for the identification and characterization of small mineral fibres, with little or no sample preparation Such spectra are sensitive to the composition of the mineral and can often be used to distinguish between similar species The technique can be employed for the identification of single micrometre-sized fibres Vibrational spectra were obtained from five asbestos reference standards for comparison with four non-fibrous analogues The different species such as amosite, anthophyllite, chrysotile, crocidolite and tremolite give distinct spectra Apparently no important differences appear between spectra of asbestos fibres and their non-fibrous forms, except in the OH- stretching region For each spectrum, all peaks were listed in order to determine spectral features The reference spectra were used for the identification of known and unknown (industrial samples) fibres on cellulose acetate filters © 1997 John Wiley & Sons, Ltd
TL;DR: In this paper, the activation of molecular oxygen on the surface of cerium oxide and the reactivities of surface oxygen species with methane and ethane were studied by means ofin situconfocal microprobe Raman spectroscopy in the temperature range 298-1023 K.
Abstract: The activation of molecular oxygen on the surface of cerium oxide and the reactivities of surface oxygen species with methane and ethane were studied by means ofin situconfocal microprobe Raman spectroscopy in the temperature range 298–1023 K. The results showed that O22-, O2- and O2δ- (0<δ<1) adspecies formed on the surface of an oxygen-pretreated cerium oxide sample when the temperature was below 423 K. As the temperature was increased, some oxygen species desorbed from the sample surface. At 1023 K, only the CeO2F2gpeak (at 449 cm-1) and O2- species (at 1159 cm-1) were observed on the CeO2 surface. In the absence of gaseous oxygen, ethane reacted with lattice oxygen species and diatomic oxygen adspecies, including O22-, O2- and O2δ- (0<δ<1) below 373 K. In contrast, the reactions of methane with superoxide and lattice oxygen species apparently did not take place until the temperature was increased to 1023 K. © 1997 by John Wiley & Sons, Ltd.
TL;DR: In this paper, the pigments used in the decoration of medieval (13-14th century) pottery were analyzed using Raman microscopy x-ray powder diffractometry and X-ray photoelectron spectroscopy.
Abstract: Fragments from the archaeological site of Castel Fiorentino (Foggia, Italy) were analysed by Raman microscopy x-ray powder diffractometry and x-ray photoelectron spectroscopy to determine the pigments used in the decoration of this medieval (13–14th century) pottery. Lapis lazuli was identified as the blue pigment and such decoration was established as a characteristic of this pottery class. The brown–black pigment was identified as a manganese oxide, probably MnO2. The qualitative composition of the glaze was also shown to include tin(IV) oxide (cassiterite) and lead-containing oxides, along with other oxides. © 1997 by John Wiley & Sons, Ltd.
TL;DR: In this article, Fourier Transform Raman spectroscopy was applied to three coloured pigment samples and a white pigment from biodeteriorated sixteenth century Italian Renaissance frescoes located at the Palazzo Farnese, Caprarola, Italy.
Abstract: The application of Fourier Transform (FT) Raman spectroscopy to three coloured pigment samples and a white pigment from biodeteriorated sixteenth century Italian Renaissance frescoes located at the Palazzo Farnese, Caprarola, Italy, is reported. The samples provide a difficult example for Raman spectroscopic characterization owing to the complexity of the biodeteriorated encrustation, which includes incorporated substratal material and lichen metabolic by-products. Some of the pigments used were identified and the potential of FT-Raman spectroscopy as a means of aiding conservation of such artistic artefacts was demonstrated. © 1997 John Wiley & Sons, Ltd.
TL;DR: In this article, it was shown that Dirina massiliensis forma sorediata is capable of chemically disturbing substrata to depths of almost 2 mm in under 12 years and converting the substrata into substantial quantities of calcium oxalate.
Abstract: Lichens, formerly considered as weathering agents in a geological context, are shown to be capable of biodeteriorating stone substrata within a relatively short time-scale. Detailed Raman spectroscopic studies have demonstrated the highly destructive properties of calcium oxalate produced by lichen thalli. Dirina massiliensis forma sorediata is capable of chemically disturbing substrata to depths of almost 2 mm in under 12 years and converting the substrata into substantial quantities of calcium oxalate. Studies of disfigurement of English church walls assumed to have been rendered with a decorative or protective surface via restoration, have also been proved spectroscopically to be the result of this lichen’s biodeteriorative action. © 1997 John Wiley & Sons, Ltd.
TL;DR: In this article, the spectrum of indigotin shows extra bands assigned to vibrational modes of Bu symmetry, indicating a loss of the centrosymmetry of the molecule and an alteration of its planarity due to the dyeing process.
Abstract: Reference (natural and synthetic) indigo samples were analysed by Raman spectrometry and only indigotin was detected. ‘Jeans’ refers to a specific garment with respect to both the dye, indigo, and the garment cut; from reference spectra of blue-dyed fibres and threads from garments, it is straightforward to observe by Raman microspectrometry the spectra of dyes fixed on threads without chemical pretreatment. On these supports, the spectrum of indigotin shows extra bands assigned to vibrational modes of Bu symmetry, indicating a loss of the centrosymmetry of the molecule and an alteration of its planarity due to the dyeing process. © 1997 by John Wiley & Sons, Ltd.
TL;DR: In this article, the Fourier transform Raman spectroscopy (FT-Raman) was applied to two pigment samples of mediaeval wall paintings and the identification of the pigments used were reported.
Abstract: The application of Fourier transform (FT) Raman spectroscopy to two pigment samples of mediaeval wall paintings and the identification of the pigments used are reported. The potential of FT-Raman spectroscopy as a non-destructive technique to examine valuable artistic and archaeological artefacts is demonstrated. © 1997 by John Wiley & Sons, Ltd.