Pigment analysis by Raman microscopy and portable X-ray fluorescence (pXRF) of thirteenth to fourteenth century illuminations and cuttings from Bologna.

Non-destructive pigment analysis by Raman microscopy (RM) and portable X-ray fluorescence (pXRF) has been carried out on some Bolognese illuminations and cuttings chosen to represent the beginnings, evolution and height of Bolognese illuminated manuscript production. Dating to the thirteenth and fourteenth centuries and held in a private collection, the study provides evidence for the pigments generally used in this period. The results, which are compared with those obtained for other north Italian artwork, show the developments in usage of artistic materials and technique. Also addressed in this study is an examination of the respective roles of RM and pXRF analysis in this area of technical art history.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.

Archaeometric study of black-coated pottery from Pompeii by different analytical techniques.

Complementary spectroscopic methods were used to characterize ceramic body and black coating of fine pottery found at Pompeii (Italy). This has enabled us to investigate local productions and to clarify the technological changes over the 4th-1st centuries BC. Two different groups of ceramics were originally distinguished on the basis of macroscopic observations. Optical microscopy (OM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) seem to indicate the usage of the same raw materials for the production of black-coated ceramics at Pompeii for about three centuries. Raman microscopy (RM) and micro-analysis (SEM/EDS) suggest different production treatments for both raw material processing and firing practice (duration of the reducing step and the cooling rate).

High-throughput continuous hydrothermal synthesis of nanomaterials (part II): unveiling the as-prepared CexZryYzO2-δ phase diagram.

High-throughput continuous hydrothermal flow synthesis was used to manufacture 66 unique nanostructured oxide samples in the Ce-Zr-Y-O system. This synthesis approach resulted in a significant increase in throughput compared to that of conventional batch or continuous hydrothermal synthesis methods. The as-prepared library samples were placed into a wellplate for both automated high-throughput powder X-ray diffraction and Raman spectroscopy data collection, which allowed comprehensive structural characterization and phase mapping. The data suggested that a continuous cubic-like phase field connects all three Ce-Zr-O, Ce-Y-O, and Y-Zr-O binary systems together with a smooth and steady transition between the structures of neighboring compositions. The continuous hydrothermal process led to as-prepared crystallite sizes in the range of 2-7 nm (as determined by using the Scherrer equation).

Anatase: important industrial white pigment and date-marker for artwork.

Barium sulfate, BaSO4, is shown by Raman microscopy to be readily identifiable in early (1920s) industrially produced anatase (TiO2) and thus, if present, may act as a date marker for early industrial anatase. Later processes (except that for producing Titanox B) did not involve usage of barium sulfate. The matter is relevant to the possible dating of certain artwork.

Rayleigh, Ramsay, Rutherford and Raman--their connections with, and contributions to, the discovery of the Raman effect.

The key contributions of the four great Nobel Laureates - Lord Rayleigh, Sir William Ramsay, Lord Rutherford and Sir Chandrasekhara Raman - to the understanding of light scattering, to the identification and classification of the rare gases, and to the discovery in 1928 of the Raman effect are outlined. The interactions between these scientists are explored, in particular those of Rayleigh with Ramsay (in establishing the physics and chemistry of the rare gases), Ramsay with Rutherford (on studies of the radioactivity of radium dibromide and on the discovery of radon and its position in the periodic table), and Rutherford with Raman (in supporting Raman's career via the Royal Society and as a nominee for the Nobel Prize). The resilience and dedication of these scientific pioneers is emphasised, noting in particular that Rutherford and Raman emerged with success from unlikely backgrounds and from countries far removed from the then centres of scientific excellence. Key developments from 1928 onwards in the light sources used for the excitation of Raman spectra and in the detectors of Raman scattered radiation are outlined. Attention is drawn to the mounting number of scientific areas which continue to be opened up by Raman microscopy and many other derived techniques such as SERS, TERS, etc.

Raman spectroscopy analysis of pigments on 16-17th c. Persian manuscripts.

The palette of four Persian manuscripts of the 16th and 17th centuries were established by Raman microscopy to include lazurite, red lead, vermilion, orpiment, a carbon-based black, lead white, malachite, haematite, indigo, carmine and pararealgar. The first five pigments were identified on all four manuscripts, as previously found for other Islamic manuscripts of this period. The findings were compared with information available in treatises on Persian painting techniques. Red lead, although identified on all of the manuscripts analysed in this study as the main red pigment, is seldom mentioned in the literature. Two unusual pigments were also identified: the intermediate phase between realgar and pararealgar in the manuscript Timur namah, and carmine in the manuscript Shah namah. Although the established palette comprises few pigments, it was found that the illuminations were enhanced by the use of pigment mixtures, the components of which could be identified by Raman microscopy.

High-throughput continuous hydrothermal flow synthesis of Zn-Ce oxides: unprecedented solubility of Zn in the nanoparticle fluorite lattice.

High-throughput continuous hydrothermal flow synthesis has been used as a rapid and efficient synthetic route to produce a range of crystalline nanopowders in the Ce-Zn oxide binary system. High-resolution powder X-ray diffraction data were obtained for both as-prepared and heat-treated (850 degrees C for 10 h in air) samples using the new robotic beamline I11, located at Diamond Light Source. The influence of the sample composition on the crystal structure and on the optical and physical properties was studied. All the nanomaterials were characterized using Raman spectroscopy, UV-visible spectrophotometry, Brunauer-Emmett-Teller surface area and elemental analysis (via energy-dispersive X-ray spectroscopy). Initially, for 'as-prepared' Ce(1-x)Zn(x)O(y), a phase-pure cerium oxide (fluorite) structure was obtained for nominal values of x=0.1 and 0.2. Biphasic mixtures were obtained for nominal values of x in the range of 0.3-0.9 (inclusive). High-resolution transmission electron microscopy images revealed that the phase-pure nano-CeO(2) (x=0) consisted of ca 3.7 nm well-defined nanoparticles. The nanomaterials produced herein generally had high surface areas (greater than 150 m(2) g(-1)) and possessed combinations of particle properties (e.g. bandgap, crystallinity, size, etc.) that were unobtainable or difficult to achieve by other more conventional synthetic methods.

Raman microscopy and x-ray fluorescence analysis of pigments on medieval and Renaissance Italian manuscript cuttings.

Italian medieval and Renaissance manuscript cuttings and miniatures from the Victoria and Albert Museum were analyzed by Raman microscopy to compile a database of pigments used in different periods and different Italian regions. The palette identified in most manuscripts and cuttings was found to include lead white, gypsum, azurite, lazurite, indigo, malachite, vermilion, red lead, lead tin yellow (I), goethite, carbon, and iron gall ink. A few of the miniatures, such as the historiated capital "M" painted by Gerolamo da Cremona and the Petrarca manuscript by Bartolomeo Sanvito, are of exceptional quality and were analyzed extensively; some contained unusual materials. The widespread usage of iron oxides such as goethite and hematite as minor components of mixtures with azurite is particularly notable. The use of a needle-shaped form of iron gall ink as a pigment rather than a writing material was established by both Raman microscopy and x-ray fluorescence spectroscopy for the Madonna and Child by Franco de' Russi.

Continuous hydrothermal synthesis of extensive 2D sodium titanate (Na2Ti3O7) nano-sheets.

A novel and rapid and continuous hydrothermal route to the synthesis of extensive ultra-thin 2D sodium titanate (Na(2)Ti(3)O(7)) nano-sheets using a superheated water flow at 450 degrees C and 24.1 MPa as a crystallizing medium is described. High resolution electron microscopy of the sheets revealed that they were a few layers thick and largely uncurled, highly crystalline despite their very short time under hydrothermal flow conditions. The sodium titanate sheets possessed excellent photocatalytic activity for decolourisation of methylene blue dye.

Spectroscopic investigations of Bourdichon miniatures: masterpieces of light and color.

Metallic bismuth, pyrite (FeS2), and specular hematite (Fe2O3) were found to have been used extensively on two miniatures taken from the Book of Hours of Louis XII by Jean Bourdichon, painter at the Royal Court of France between the end of the 15th and the beginning of the 16th centuries. These unusual materials were identified, together with thirteen other more traditional pigments and dyes, by Raman microscopy and X-ray fluorescence. Pyrite was found in many areas, suggesting that it may have been deliberately added as a pigment. The luminary quality of both miniatures was enhanced by the extensive use of shell gold throughout, but other less common materials such as specular hematite and mosaic gold were also utilized. Metallic bismuth was used, alone or in admixture with other pigments, to create a soft gray color. Its identification as a paint material was complemented by the study of the optical and visual properties of standard samples of metallic bismuth and several bismuth compounds. Evidence for the use of a bismuth pencil was also found.

Characterization of Pousão pigments and extenders by micro-X-ray diffractometry and infrared and Raman microspectroscopy.

Seventeen samples from paintings by the distinguished 19th century Portuguese painter, Henrique Pousão, were characterized by micro-X-ray diffractometry and infrared and Raman microspectroscopy. The main advantages and limitations of each technique for pigment identification are outlined, revealing the need for the use of complementary techniques. Pousão's palette is discussed.

Mixed valence: origins and developments.

Mixed-valence compounds were recognized by chemists more than a century ago for their unusual colours and stoichiometries, but it was just 40 years ago that two seminal articles brought together the then available evidence. These articles laid the foundations for understanding the physical properties of such compounds and how the latter correlate with molecular and crystal structures. This introduction to a discussion meeting briefly surveys the history of mixed valence and sets in context contributions to the discussion describing current work in the field.

The Gutenberg Bibles: analysis of the illuminations and inks using Raman spectroscopy.

The King George III copy of the Gutenberg Bible, held at the British Library, has been analyzed using Raman spectroscopy to determine the palette of pigments used in the illuminations on this work. The palette is found to comprise cinnabar/vermilion, lead tin yellow (type 1), carbon-based black, azurite, malachite, an organo-copper complex (a "verdigris"), calcium carbonate (chalk), gypsum, gold leaf, and basic lead carbonate ("lead white"). This is in agreement with contemporary descriptions of the pigments used for the illuminations. One pigment could not be identified, specifically the organic dark red/purple color used for the foliage. The palette of this copy of the Gutenberg Bible has been compared with those used for six other copies, held at Eton College and Lambeth Palace, England, the Bibliothèque Mazarine and the Bibliothèque nationale de France, and the Staatsbibliothek zu Berlin and the Niedersachsische Staats- und Universitatsbibliothek (SUB) Göttingen, Germany. The palettes are shown to be similar to one another, even though the styles of the primary illuminations differ. The two Gutenberg Bibles held in Germany, printed on vellum, have the more expensive palettes, which include lazurite. The SUB Göttingen copy has the most extensive palette with 16 pigment-related materials having been identified.

A matrix isolation study of the photochemically induced reactions of nitrogen dioxide with 1,2-dibromoethene and 1,2-dichloroethene using Fourier transform infrared spectroscopy.

Photolyses of matrices of either BrCHCHBr/NO2/Ar or ClCHCHCl/NO2/Ar using quartz-filtered radiation (lambda>240 nm) led to the appearance of infrared bands attributable to carbonyl, carbon monoxide, and ketene species; no bands belonging to a precursor complex NO2cdots, three dots, centeredXCHCHX (where X=Br or Cl) were observed upon matrix deposition. The possible reaction pathway is discussed.

Pigment identification by spectroscopic means: evidence consistent with the attribution of the painting Young Woman Seated at a Virginal to Vermeer.

Technical examination of the painting Young Woman Seated at a Virginal by cross section and polarized light microscopy, chemical tests, surface microscopy, energy-dispersive X-ray analysis, and Raman microscopy has led to the identification of the pigments lead tin yellow (type I), lazurite, vermilion, calcite, lead white, red and yellow iron oxides, umber, lamp black, and green earth on the canvas. These pigments are entirely typical of Vermeer's palette and are consistent with a large body of other technical and art historical findings on paintings by Vermeer and other Dutch 17th century artists. While not authenticating the painting as being by Vermeer, the results provide further critical material that is consistent with this attribution. This case study also provides an opportunity to outline the role of analytical and forensic sciences in the examination and attribution of art objects.

Thienyl carboxylate ligands bound to and bridging MM quadruple bonds, M = Mo or W: models for polythiophenes incorporating MM quadruple bonds.

A series of compounds of the form [M(2)L(4)] and [[((t)()BuCO(2))(3)M(2)](2)(mu-L')] have been made where M = Mo or W, L = a thienyl, bithienyl, or terthienyl carboxylate, and L' = a corresponding thienyl dicarboxylate. The electronic absorption spectra are reported and the electronic structures discussed. Intense metal-to-ligand charge transfer bands traverse the visible and near-IR regions of the electronic absorption spectrum. The compounds show reversible metal-based oxidations and quasireversible ligand-based reductions. The molecular structure of Mo(2)(O(2)C-2-Th)(4).2THF is reported, on the basis of a single crystal X-ray diffraction study. These compounds provide insight into the expected properties of related dimetalated polythiophenes incorporating MM quadruple bonds.

Electronically-coupled tungsten-tungsten quadruple bonds: comparisons of electron delocalization in 3,6-dioxypyridazine and oxalate-bridged compounds.

The preparation of the 3,6-dioxypyridazine-bridged tungsten complex, [W(2)(O(2)C(t)Bu)(3)](2)(mu-H(2)C(4)N(2)O(2)), I, is described, along with its single-electron oxidized cation, I(+), formed in the reaction between I and Ag(+)PF(6)(-). Compound I has been structurally characterized as a PPh(3) adduct, and I(+)PF(6)(-) as a THF solvate, by single-crystal X-ray studies. The geometric parameters of these compounds compare well with those calculated for the model compounds [W(2)(O(2)CH)(3)](2)(mu-H(2)C(4)N(2)O(2)) and [W(2)(O(2)CH)(3)](2)(micro-H(2)C(4)N(2)O(2))(+) by density functional theory employing the Gaussian 98 and 03 suite of programs. The calculations indicate that the two W(2) centers are strongly coupled by M(2) delta-to-bridge pi-bonding, and further coupled by direct M(2)...M(2) bonding. Compound I is purple and shows an intense absorption in the visible region due to a metal-to-bridge charge transfer and, with excitation within this absorption, compound I exhibits pronounced resonance Raman bands associated with symmetric vibrations of the bridge and the M(4) unit. The cyclic voltammogram of I in THF, the EPR spectrum of I(+)PF(6) in 2-MeTHF and the electronic absorption spectrum of I(+)PF(6)(-) in THF are consistent with electron delocalization over both W(2) units. These new data are compared with previous data for the molybdenum analogue, related oxalate-bridged compounds and closely related cyclic polyamidato-bridged Mo(4)-containing compounds. It is proposed that, while the electronic coupling occurs principally by an electron-hopping mechanism for oxalate-bridged compounds, hole-hopping contributes significantly in the cases of the amidate bridges and that this is more important for M = Mo than for M = W. Furthermore, for Class III fully delocalized mixed-valence compounds, the magnitude of K(c), determined from electrochemical methods, is not necessarily a measure of the extent of electron delocalization.

Superstructures of donor packing arrangements in a series of molecular charge transfer salts.

Three conducting BEDT-TTF charge-transfer salts with tris(oxalato)metallate anions have unit cells containing both[small alpha] and [small beta][double prime] donor packing motifs.