A preliminary Raman investigation of the ionic liquid N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR(13)TFSI) and its 2/1 complex with the lithium salt LiN(SO(2)CF(3))(2) is reported. The study was performed over a temperature range extending from -100 to +60 degrees C, i.e., with PYR(13)TFSI in the crystalline and melt states. For comparison purposes, the study was extended to PYR(13)I, which is the precursor used in the synthesis of PYR(13)TFSI.

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Pure ground tungsten trioxide WO3 and (1−x)WO3−y⋅xReO2 mixtures were studied by x-ray absorption spectroscopy, x-ray powder diffraction and Raman spectroscopy in comparison with hydrogen bronzes HxWO3 and hydrogenated calcium tungstate CaWO4:H. It was found that a grinding of pure WO3 leads to a decrease of the crystallites size and a development of the bluish coloration. The color change was found to be reversible under moderate heat treatment or after storage in oxidizing atmosphere and is attributed to the reduced W5+ ions, located at the surface of freshly ground powder. The (1−x)WO3−y⋅xReO2 mixtures were found to be composed of monoclinic/orthorhombic WO3 and orthorhombic ReO2 phases with a grain boundary containing reduced W5.7+ ions which are mainly responsible for the compound color at low rhenium ion concentrations. In both cases, the W(6−z)+ (0<z⩽1) color centers are responsible for strong optical absorption resulting in the dramatic decrease of the total Raman intensity. The structural models of free surface in pure ground WO3 and bulk WO3/ReO2 intragrain boundary in (1−x)WO3−y⋅xReO2 mixtures are proposed and discussed.

Polymorphism in the growth of titanyl phthalocyanine films on dielectric substrates has been systematically studied by UV absorption and micro-Raman analyses, correlating structure and optical properties. We explored different growth regimes as a function of substrate temperature and growth rate using hyperthermal seeded supersonic beams. We identify and discuss specific signatures in micro-Raman spectra specifically correlated to the different phases and demonstrate the unprecedented ability of growing crystalline films and controlling the relative abundance of the different phases (amorphous, phase I, and phase II) by the beam parameters. We envisage the very promising perspective of controlling polymorphism at low temperatures via supersonic beam growth, paving the way for better performing devices.

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Spectroscopic ͑Raman, NMR, impedance spectroscopy͒, and thermal ͓differential scanning calorimetry ͑DSC͔͒ techniques have been used to study the solvation mechanism of lithium ions in ethylene carbonate ͑EC͒-propylene carbonate ͑PC͒ concentrated solutions. For values of N ϭ͓Li ϩ ͔/͓ECϩPC͔р0.2 all the cations are solvated by ϳ4 solvent molecules and interaction chiefly takes place between Li ϩ and the ring oxygens. For NϾ0.2 a part of Li ϩ ions begins to form complexes with two solvent molecules ͑sandwich configuration͒. At NХ0.5 nearly all cations are complexed, and a crystalline compound is formed at room temperature. For higher values of N a reassociation of the salt takes place.

The ancient town of Pompei offers a unique opportunity to study in detail many aspects of the every day life during the Roman early imperial age. The application of micro-Raman spectroscopy can be of great help in performing a reasonably rapid comparative analysis of the mortars, quite useful to ascertain the degree of uniformity of the technical recipes among the various building firms and the eventual technical evolution in the time; moreover, the individuation of minerals of specific geographical origins can give useful information about the extension of commercial intercourses. An example of a micro-Raman investigation on building materials is reported in this work, concerning the analysis of the mortars coming from different points of the wall in the 'The House of the Wedding of Hercules'. Remarkable differences between ancient and modern mortars are found, allowing a discrimination that can be useful in the case of historical building which underwent several restoration works.

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