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Ground granulated blast furnace slags (GGBS) are glassy by-products from iron production that are commonly used as supplementary cementitious materials in blended cements. The glass structure of seven industrial GGBS was investigated by Raman and nuclear magnetic resonance spectroscopies. The complex composition of the slags induced multiple analytical challenges. Under usual continuous excitation, the Raman signal was masked by strong luminescence, so that analysis was carried out on a time-resolved Raman (TRR) device. TRR allowed to eliminate luminescence and resulted in exploitable spectra that showed variations in line with theoretical NBO/T values. The analysis of 27Al and 29Si NMR spectra was complicated by the presence of paramagnetic nuclei and the wide variety of environments. Nevertheless, 27Al NMR showed that Al was present as a network former, mainly in fourfold coordination and careful analyses of 29Si NMR spectra allowed the comparison of glass network polymerization of industrial GGBS in line with the theoretical NBO/T based on their composition. [ABSTRACT FROM AUTHOR]

Detailed crystallographic information provided by X‐ray diffraction (XRD) is complementary to molecular information provided by Raman spectroscopy. Accordingly, the combined use of these techniques allows the identification of an unknown compound without ambiguity. However, a full combination of Raman and XRD results requires an appropriate and reliable reference database with complete information. This is already available for XRD. The main objective of this paper is to introduce and describe the recently developed Raman Open Database (ROD, http://solsa.crystallography.net/rod). It comprises a collection of high‐quality uncorrected Raman spectra. The novelty of this database is its interconnectedness with other open databases like the Crystallography Open Database (http://www.crystallography.net/cod and Theoretical Crystallography Open Database (http://www.crystallography.net/tcod/). The syntax adopted to format entries in the ROD is based on the worldwide recognized and used CIF format, which offers a simple way for data exchange, writing and description. ROD also uses JCAMP‐DX files as an alternative format for submitted spectra. JCAMP‐DX files are compatible to varying degrees with most commercial Raman software and can be read and edited using standard text editors. [ABSTRACT FROM AUTHOR]

Raman spectroscopy at high temperature has been applied to study in situ the microstructure of the solution in a Cs2O-B2O3-MoO3 growth system. A crystal-solution interface was observed. The BO groups consist of spiral chains based on B3O4Ø2 rings in the solution (Ø is a bridging O atom). The Raman spectrum of the solution indicates that MoO4 tetrahedra existed in the growth system. The nonbridging O atoms of the chains combined with the MoO4 groups, which decreased the viscosity. The Raman spectra near the interface show that at the boundary an isomerization reaction from three- to four-coordinated boron occurred. The formation of B3Ø7 triborate groups occurred. The morphology of the CsB3O5 crystal resulting from spontaneous crystallization was observed to correspond to our expectations. [ABSTRACT FROM AUTHOR]

High-purity fused silicas (800-1000 ppm OH) have been studied by in situ Raman scattering in the 1000°-1400°C temperature range, with a particular interest on the behavior under long annealing cycles. We evidence for the first time the relaxation times of silicas in the vicinity of Tg by direct monitoring on time-wavenumber 2D representations of the main broad band at 440 cm-1. These relaxation times appear longer than expected through existing descriptions, and could serve as indicative needed annealing times for thermal treatments and changes of fictive temperature. [ABSTRACT FROM AUTHOR]

Organic molecules are prime targets in the search for life on other planetary bodies in the Solar System. Understanding their preservation potential and detectability after ionic irradiation, with fluences potentially representing those received for several millions to billions of years at Mars or in interplanetary space, is a crucial goal for astrobiology research. In order to be able to perform in situ characterization of such organic molecules under ionic irradiation in the near future, a feasibility experiment was performed with polymer test samples to validate the optical configuration and the irradiation chamber geometry. We present here a Raman in situ investigation of the evolution of a series of polymers during proton irradiation. To achieve this goal, a new type of Raman optical probe was designed, which documented that proton irradiation (with a final fluence of 3.1014 at·cm–2) leads to an increase in the background level of the signal, potentially explained by the scission of the polymeric chains and by atom displacements creating defects in the materials. To improve the setup further, a micro-Raman probe and a temperature-controlled sample holder are under development to provide higher spectral and spatial resolutions (by reducing the depth of field and laser spot size), to permit Raman mapping as well as to avoid any thermal effects. Graphical Abstract [ABSTRACT FROM AUTHOR]

The exploitation of the data acquired by Raman spectroscopy on UO 2 related materials requires the understanding of the so-called defect peaks. To do so, we measured the Raman spectrum of a He-implanted UO 2 sample as a function of temperature. Two annealing steps are evidenced that correspond to known annealing temperatures reported in literature. These results are discussed in order to identify what defect could be at the origin of the Raman defect peaks. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the disordered network of calcium phosphate glasses is investigated by Raman scattering and 31P magic angle spinning (MAS) solid-state NMR spectroscopies. The use of both spectroscopies in a combined approach allows drawing a detailed understanding of the structure of these glasses. The P―O―P connectivity between successive PO4 tetrahedra is probed using through-bond double quantum–single quantum (DQ–SQ) and triple quantum–single quantum (TQ–SQ) MAS NMR correlation experiments. Over the broad range of glass compositions studied here, two very different phosphate network topologies are encountered. The results obtained for the polyphosphate compositional range (above 50mol% Ca) allow determining the phosphate chain-length distribution in the glass as a function of the modifier cation content. For the ultraphosphate region (below 50mol% Ca), the network topology undergoes a sudden change close to 39mol% Ca which can be interpreted in terms of a rigidity transition. [Copyright &y& Elsevier]

Lowering the temperature of CNT synthesis before any attempts of integration is a technical challenge. The improvement of CNT carpet growth on Ni/TiN/SiO 2 /Si by previously reducing the size of Ni particles using H 2 plasma prior to be exposed to H 2 :C 2 H 4 plasma is studied. Different techniques, SEM, in situ Raman, NEXAFS, XPS and TEM were combined to investigate the growth rate and the quality of CNT films. An original use of in situ Raman spectroscopy allowed us to determine the increase of sample surface temperature in contact with H 2 plasma through Si anharmonicity. Finally it was possible to grow CNT carpets by PECVD with a process temperature of 480 °C. [ABSTRACT FROM AUTHOR]

The far-and mid-infrared reflectivity spectra of two carbon layers deposited on pure (100) silicon substrates by DC magnetron sputtering were investigated at room temperature in the 10–5000 cm −1 wavenumber range. Their structural and textural features were also studied by combining Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM), X-Ray Reflectivity (XRR) and Rutherford Backscattering Spectroscopy (RBS). The set of results was used to discuss afterwards the influence of the texture on the infrared properties at varying length scale. Thereby, the two layers were found to be heterogeneous as assessed by RBS, XRR and FESEM and their thicknesses had been measured by XRR and FESEM. The information on the structural organization and “crystallite” size was given by Raman spectroscopy. The influence of both the textural and structural parameters on the measured infrared reflectivity spectra was discussed. Finally, a methodology was proposed to recover the intrinsic index of refraction and the intrinsic index of absorption of each layer. [ABSTRACT FROM AUTHOR]

Abstract: Olivine is one of the well-suited materials for fluidized bed reactor technology. After calcination at high temperature, olivine undergoes phase transformations resulting in dehydration and oxidation of fayalite to hematite and magnetite. The transformation mechanisms of olivine subjected to a calcination process at 1400°C for 4h are studied. Calcined olivine is characterized by X-Ray Diffraction (XRD), in situ XRD at varying temperatures and Raman spectroscopy. This paper explains the contribution of Raman spectroscopy to the study of iron oxide with regard to XRD. The heterogeneous distribution of hematite, magnetite and forsterite in the calcined material is exhibited by Raman mapping. [Copyright &y& Elsevier]

Abstract: The graphitic layered compound C6N9H3·HCl was prepared by reaction between melamine and cyanuric chloride under high pressure–high temperature conditions in a piston cylinder apparatus and characterised using SEM, powder X-ray diffraction, UV Raman and near-IR Fourier transform Raman spectroscopy with near-IR excitation. Theoretical calculations using density functional methods permitted evaluation of the mode of attachment of H atoms to nitrogen sites in the structure and a better understanding of the X-ray diffraction pattern. Broadening in the UV and near-IR FT Raman spectra indicate possible disordering of the void sites within the graphitic layers or it could be due to electron–phonon coupling effects. [Copyright &y& Elsevier]