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Gadolinium Zirconate nanoparticles were synthesized by Co-precipitation and Ball milling techniques. In this study, the effect of the synthesis technique and calcination temperature on the structural, morphological and thermal properties were investigated. The thermal properties examined showed that the GZ nanoparticles obtained from CP technique suffered two-fold weight loss as compared to BM technique. The SEM results revealed the formation of agglomerated particles. However, TEM results confirms the formation of nanoparticles of 10.5 nm and 8 nm by BM and CP techniques respectively. GZ particles obtained through CP technique showed better uniformity of particle size over BM technique. The functional groups of the nanoparticle were studied using FT-IR spectroscopy analysis. The XRD results confirm the formation of defect-fluorite structure and pyrochlore structure for the samples calcined at 1100 °C and 1400 °C (BM) respectively. The formation of the corresponding structures was further confirmed by Raman Spectroscopy. The thermal conductivity of the nanoparticle produced by ball milling and co-precipitation technique is almost same. As compared to NiCrAlY and uncoated substrate materials, the micro hardness of the GZ coatings has the maximum hardness of 594.6 HV, indicating the improved hardness behavior of TBC system. [ABSTRACT FROM AUTHOR]

• Crystals formed from 2-nitro-4-methylanilinium benzenesulfonatein water. • Crystal structure: P2 1 /c group, monoclinic system, four molecules per unit cell. • Lattice parameters: a = 13.242 (4) Å, b = 15.296 (5) Å, c = 6.865 (3) Å and the volume V = 1389.3(9) Å3. • Theoretical investigations at B3LYP/6–311++ G (d,p) level for molecular properties. • UV–Vis and HOMO-LUMO studies in gas phase and solvents (acetone, benzene, etc.). • Hirshfeld surfaces and 2D fingerprint plots for crystal's constituent elements. • Molecular docking and drug-likeness evaluation for potential drug candidacy. Single crystals of 2-nitro-4-methylanilinium benzenesulfonate were successfully grown from a water solution and the crystalline arrangement was determined through XRD analysis and confirms the centrosymmetric space group P2 1 /c of the monoclinic system, with four molecules per unit cell. Furthermore, theoretical investigations were conducted at the B3LYP/6–311++ G (d,p) level to explore the molecular structure, vibrational spectra, and bonding interactions of the grown compound and provides insights into the fundamental properties of the compound and its molecular behavior. In addition to theoretical studies, FMO & UV–Visible techniques were employed to investigate the electronic transitions and energy levels of the compound in both gas phase and various solvents (including water, methanol, acetone, benzene, heptane, and cyclohexane). This comprehensive analysis allows for an understanding of how the compound's electronic properties are influenced by solvent effects, providing valuable information for its potential applications. Furthermore, Hirshfeld surfaces (HS) and 2D fingerprint plots were utilized to analyze the interactions among the crystal's constituent elements and the factors influencing its structure. Finally, molecular docking evaluations were performed to assess the potential of the synthesized compound, 2-nitro-4-methylanilinium benzenesulfonate, as a drug candidate. This computational approach helps predict how the compound may interact with biological targets, providing valuable information for its potential therapeutic applications. Overall, this multidisciplinary approach offers a comprehensive understanding of the synthesized compound's structure, properties, and potential pharmaceutical relevance. [Display omitted] [ABSTRACT FROM AUTHOR]

The ability to identify and characterize microorganisms from tiny sample volumes in a rapid and reliable way is the first and crucial step in the diagnostics of microbial infections. Ideal analytical techniques would require minimal and low-cost sample preparation, permit automatic analysis of many serial samples, and allow rapid classification of present microorganisms against a stable database. Current practice, however, is far from this ideal; a typical analytical procedure might require a few days. Delayed laboratory results might lead, for example, to progress/spread of the infection, more serious condition of the patient, even death, prescription of inappropriate antibiotics that could be ineffective against causative agents and may as well contribute to the emerging problem of drug resistance in microorganisms. Several studies confirmed that surface enhanced Raman scattering (SERS) is capable of a rapid identification and discrimination of biological samples including medically relevant bacteria. A typical spectrum contains a wealth of information indicative of the cellular content of nucleic acids, purine bases, proteins, carbohydrates, and lipids. Such a spectrum functions as a cellular ‘fingerprint’ and serves as a sensitive indicator of the physiological state of the cell which in turn enables to differentiate cell types, actual physiological states, nutrient conditions, and phenotype changes. Consequently, the focus of this review is on the SERS spectra of bacteria which result from secreted metabolic substances – the purine bases – which are a common feature in the label-free SERS research related to clinical diagnostics of pathogens. Here is the review of the current status of SERS applications on bacteria. A special attention is given to the efforts of profiling antimicrobial susceptibility at clinically relevant species, which in turn has a great potential for use in routine point-of-care (POC) tests. Thus, early and accurate infection disease management can be provided at the bedside or at remote care centres.

Discrimination of yellow and brown flaxseed cultivars was made based on diffusion reflectance FT-NIR spectra of whole seeds. The spectra of flaxseed kernels, hulls, defatted flours, and oils were also measured for comparison. Hierarchy cluster analysis (HCA) and principal component analysis (PCA) were used for the discrimination. Multivariate analyses of FT-NIR spectra led to satisfactory discrimination of all flaxseed cultivars of this study mainly according to the nutritionally important fatty acid composition that was confirmed by comparison with the corresponding spectra of flaxseed kernel and oil. By contrast, spectral features of proteins, polysaccharides, and tannins predominated in the FT-NIR spectra of flaxseed hulls and defatted flours.

This work presents a method for determining the effective Young's modulus (E effective) and Poisson ratio of small specimens of a ternary shape memory alloy (SMA), Cu - Al - Be. The alloys were synthesized uniformly and homogeneously using various concentrations of high purity metals and formed into slabs of different geometrical shapes. The phases and fractional quantities of each sub-alloy composing the SMA were determined using SEM/EDS data and the lever rule, and confirmed by matching computed and measured X-ray diffraction peak patterns. The E effective was determined using the rule of mixtures, employing elastic moduli obtained from Ab initio (Density functional theory) calculations. To address the challenge of determining E effective experimentally for small specimens, high frequency ultrasonic waves and vibration spectroscopy were used. The E effective was then used in a 3D finite element model to compute the vibrational spectrum's resonance peaks, which were found to match those of the experimental vibrational response. The E effective was also compared to the pressure wave (P-waves) modulus recovered using non-contact ultrasound waves propagating through the sample's thickness. Discrepancies mainly occurring for alloys with the β phase were resolved by determining its anisotropic spatial Young's modulus. Overall, the presented method provides a comprehensive characterization of the mechanical properties of small alloy specimens. • The determination of the Effective Young's modulus of a Cu-Al-Be SMA was done. • EDS data, phase diagram, employed to determine the sub-alloys and %fraction. • The sub-alloys' elastic moduli were derived using Ab-intio computation. • The effective Young's moduli found using the rule of mixtures. • Validation using theoretical and experimental vibration and ultrasonic waves. [ABSTRACT FROM AUTHOR]

Discrimination of yellow and brown flaxseed cultivars was made based on diffusion reflectance FT-NIR spectra of whole seeds. The spectra of flaxseed kernels, hulls, defatted flours, and oils were also measured for comparison. Hierarchy cluster analysis (HCA) and principal component analysis (PCA) were used for the discrimination. Multivariate analyses of FT-NIR spectra led to satisfactory discrimination of all flaxseed cultivars of this study mainly according to the nutritionally important fatty acid composition that was confirmed by comparison with the corresponding spectra of flaxseed kernel and oil. By contrast, spectral features of proteins, polysaccharides, and tannins predominated in the FT-NIR spectra of flaxseed hulls and defatted flours. [ABSTRACT FROM AUTHOR]

The structure of binary xZnO–(100–x)B2O3 glass and iron-containing, 2.5Fe2O3–97.5[xZnO–(100–x)B2O3] glass with x = 40, 45, 50, and 55 mol % obtained by the melt quenching method is studied by the methods of vibrational and Mössbauer spectroscopy. It is shown that the regularities of the transformation of the local glass structure as the function of zinc oxide content are the same for the glass of both series. A relatively small addition of iron oxide results in changing glass structure on the level of superstructural groups and to the distribution of trigonal basic borate units. The concentrations of di- and trivalent iron atoms are almost independent of the composition of the glass matrix while the coordination state of Fe3+ ions is a function of the zinc oxide content in the studied glass. [ABSTRACT FROM AUTHOR]

Solid dispersions of spironolactone with Soluplus ® and polyvinylpyrrolidone were prepared by spray drying according to a mixture experimental design and evaluated for moisture content, particle size, drug solubility, crystallinity (powder X-ray diffraction and differential scanning calorimetry), and physicochemical interactions (Fourier-transform infrared spectroscopy, Raman). In vitro dissolution was evaluated for the spray dried product itself and after compression into tablets, and prediction models were derived using multiple linear regression analysis. The spray dried products consisted of amorphous drug, indicated by the absence of crystalline powder X-ray diffraction peaks. Amorphization and interactions impacted changes in the Fourier-transform infrared spectroscopy spectra in the ranges 2900-3000 cm −1 (C-H) and 1600-1800 cm −1 (C=O) and caused merging at 1690 cm −1 (C=O of lactone) and 1670 cm −1 (C=O of thioacetyl group). In the Raman spectra, amorphization and interactions resulted in disappearance of peak at 1690 cm −1 (C=O) and merging of peaks at 582 and 600 cm −1 (C-S). Hydrogen bonding between the thioacetyl group of the drug with the hydroxyl groups of Soluplus ® caused marked suppression of the peak at 1190 cm −1 (R-C(=O)-S vibration). Amorphization and interactions resulted in improved solubility and dissolution which was greatest for drug/Soluplus ® ratio 1:4 and was also demonstrated in the corresponding tablets. [ABSTRACT FROM AUTHOR]

Methane has been detected on all planets of our Solar System, and most of the larger moons, as well as in dwarf-planets like Pluto and Eric. The presence of this molecule in rocky planets is very interesting because its presence in the Earth's atmosphere is mainly related to biotic processes. Space instrumentation in orbiters around Mars has detected olivine on the Martian soil and dust. On the other hand the measurements of methane from the Curiosity rover report detection of background levels of atmospheric methane with abundance that is lower than model estimates of ultraviolet degradation of accreted interplanetary dust particles or carbonaceous chondrite material. Additionally, elevated levels of methane about this background have been observed implying that Mars is episodically producing methane from an additional unknown source, making the reasons of these temporal fluctuations of methane a hot topic in planetary research. The goal of this study is to investigate at atomic level the interactions during the adsorption processes of methane and other Mars atmospheric species (CO 2 , H 2 O) on forsterite surfaces, through electronic structure calculations based on the Density Functional Theory (DFT). We propose two models to simulate the interaction of adsorbates with the surface of dust mineral, such as binary mixtures (5CH 4 +5H 2 O/5CH 4 +5CO 2 ) and as a semi-clathrate adsorption. We have obtained interesting results of the adsorption process in the mixture 5CH 4 +5CO 2 . Associative and dissociative adsorptions were observed for water and CO 2 molecules. The methane molecules were only trapped and held by water or CO 2 molecules. In the dipolar surface, the adsorption of CO 2 molecules produced new species: one CO from a CO 2 dissociation, and, two CO 2 molecules chemisorbed to mineral surface forming in one case a carbonate group. Our results suggest that CO 2 has a strong interaction with the mineral surface when methane is present. These results could be confirmed after the analysis of the data from the upcoming remote and in-situ observations on Mars, as those to be performed by instruments on the ESA's ExoMars Trace Gas Orbiter and ExoMars rover. [ABSTRACT FROM AUTHOR]

• The present study reveal E-Wc and HB strengths in alcoholic beverages based on vibrational (FT-IR, NIR and Raman) spectrum; • Excess spectrum, two-dimensional correlation and MCR-ALS analysis are employed to improve the spectral resolution; • A wide range of alcoholic beverages as whisky , vodka , Japanese shochu/sake , Chinese rice wine / baijiu , are covered in this review. • The relationship between E-Wc and taste of alcoholic beverages is established, supplying guidance to improve their quality. Alcoholic beverages are popular throughout the world, and numerous studies have been conducted on them. Albeit most investigations focusing on composition and evolution of flavor components, several studies have suggested that the tastes and/or qualities of them are not only determined by the type and content of involved ingredients but also influenced by the supramolecular clusters between ethanol and water. However, insights into supramolecular ethanol–water clusters (E-Wc) in alcoholic beverages, especially the intrinsic relationship of them to organoleptic sensing and quality assessment, have not been elucidated systematically up to now. This review summarized the studies exploring the supramolecular E-Wc in several types of alcoholic beverages, which were revealed essentially by means of vibrational spectroscopic techniques such as infrared/near-infrared absorption and Raman scattering spectra. From different aspects and levels they revealed the structures of supramolecular E-Wc, as well as, the hydrogen bonds (HBs) strength in alcoholic beverages, respectively. Besides, two-dimensional correlation analysis has also been used as a powerful tool in the studies of alcoholic beverages which has revealed important structural information being hidden in the original spectra. Finally, beyond identifying a number of important supramolecular E-Wc by spectroscopy, the prospects and challenges in this field were also briefly discussed in the hope that it would be of interesting and help to more researchers in the fields of liquid science. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the changes of physico-mechanical properties of polyethylene during recycling stages. All raw materials were taken virgin and recycled polyethylene granules used for producing plastic bags. Initially they were identified with the vibration spectroscopy FT-IR and Raman, which marked the presence of additives in recycled samples. As recycling process was used as a micro-pilot system; comprising the melt flow index device and a universal mill grinding. Among mechanical properties that were identified were density, specific gravity, melt flow index, yield strength and elasticity modulus and tensile strength. From the results analysis were observed changes in physical and mechanical properties for polyethylene samples by recycling cycles.

The adsorptions of tryptophan (Trp) on silver or gold surfaces were investigated by surface-enhanced Raman scattering (SERS) measurements. In addition, peptides with Trp in different chain positions were studied and the adsorption sites were determined based on marker bands. The indole ring was the main group responsible for the interactions with gold nanoparticles (AuNPs). In the presence of HCl, the SERS spectra suggested that the anchoring of such peptides on AuNPs was reinforced by ionic pair interactions between protonated amine and chloride ions. The adsorptions of Trp and its derivatives on silver nanoparticles (AgNPs) show some variability in the spectral patterns, even though the enhanced carboxilate and amino features were ever ascribed as preferable adsorption site. Based on DFT calculations the vibrational assignment allows the reinterpretation of previous published works. The investigations showed that both the high affinity of indole moiety for the AuNP surfaces make these substrates adequate for studying the adsorption of peptides containing Trp and the proposed SERS assignments could be helpful for further studies of more complex structures. [ABSTRACT FROM AUTHOR]

In bacterial pathology, metallophores fabricated by bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa are exported to surrounding physiological media via a specific process to sequester and import metals, resulting in enhanced virulence of the bacteria. While these mechanisms are understood at qualitative levels, our investigation presents a complementary original view based on quantum chemical computations. Further understanding of the active centers in particular was provided for pseudopaline and staphylopine metallophores, which were described chemically and with vibration spectroscopy. Then, for complexes formed with a range of transition metal divalent ions (Ni, Cu, and Zn), description and analyses of the frontier molecular orbitals (FMOs) are provided, highlighting a mechanism of metal-to-ligand charge transfer (MLCT), based on excited-states calculations (time-dependent density functional theory (TD-DFT)) at the basis of the delivery of the metallic ionic species to the bacterial medium, leading eventually to its enhanced virulence. Such investigation gains importance especially in view of stepwise syntheses of metallophores in the laboratory, providing significant progress in the understanding of mechanisms underlying the enhancement of bacterial pathologies.

Fourier transform infrared (FT-IR) spectroscopy is an indispensable tool for identifying biologically active functional groups in uncharacterized crude samples. Here, using FT-IR spectrum analysis, we identified crude extracts of Streptomyces that have anti-malarial activities and conducted a statistical analysis of their spectra. Among the three crude microbial extracts tested herein, an aromatic amine C-N stretching functional group was observed in the spectra of Streptomyces sp. BJSG1 and BJSG4 crude extracts. These extracts showed promising activity against Plasmodium falciparum in vitro cultures with IC50 values of 0.5 for BJSG1 and 0.4µg/mL for BJSG4. The present results showed that FT-IR analysis is necessary for the primary analysis of unknown samples in anti-malarial drug development. [ABSTRACT FROM AUTHOR]

In this work we report on dissociative adsorption of deuterium (D 2 ) on bare, hydrogenated and ion beam bombarded polycrystalline and single crystalline diamond surfaces. Polycrystalline diamond films with an average grain size of ~ 300 nm were deposited on silicon substrates by hot filament chemical vapor deposition technique from methane/hydrogen gas mixture. Deposited films were characterized using Raman spectroscopy, atomic force microscopy and scanning electron microscopy to estimate the phase composition and microstructure. High resolution electron energy loss spectroscopy and direct recoil spectrometry were used to study hydrogen (deuterium) bonding configuration of the upper surface region. Near surface amorphization was achieved by 1 keV Ar + implantation at ~ 1 × 10 15 ions/cm 2 at room temperature (RT). As deposited and Ar + bombarded films are annealed to 500–1000 °C in ultra-high vacuum conditions and also under D 2 partial pressure of 5 × 10 − 6 Torr. For comparison, key experiments were repeated on the single crystal (100) diamond. Our results clearly show the preferential dissociative adsorption of D 2 on low hybridized carbon (sp/sp 2 ) states with activation temperature as low as RT, but with a lower thermal stability compared to pure diamond C D bonds. [ABSTRACT FROM AUTHOR]

The new supramolecular structure based on the toroid nanoclustered giant polyoxomolybdate (POM) Mo 138 and xanthene dye (rhodamine-B) was synthesized by a self-assembly technique in solution and was extracted in the solid state for the first time. Fluorescence studies of this structure have shown a very effective energy transfer (conditioned by the charge transfer and/or fluorescence resonance energy transfer mechanisms) from a dye molecule to a nanocluster under excitation by visible light (522 and 558 nm). The promotion of potential catalytic properties of polyoxomolybdate or revealing nonlinear optical properties could be expected there due to the presence of Mo V and Mo VI sites in Mo 138 . Raman-spectroscopy showed significant changes for vibrating bands of the rhodamine-B conditioned by the energy transfer. Investigations of the supramolecular structure by zeta-potential and size distribution measurements allowed us to determine an interaction mechanism between the components in solution. Spatial location of dye molecules on the polyoxomolybdate surface and the integrity of nanocluster Mo 138 in the supramolecular structure were found by FTIR-spectroscopy. The calculation of HOMO – LUMO electron transition of rhodamine-B by the Time-Dependent Density Functional Theory (TDDFT) technique revealed the potential overlapping between molecular orbitals of adsorbed dye molecules and POM’s surface. That is well-correlated with the overlapping of fluorescence and absorption spectrums of rhodamine-B and the nanocluster respectively. [ABSTRACT FROM AUTHOR]

The interest in the oxo-enol tautomerism of 1,3-dioxo compounds is justified by their usefulness in many synthetic fields. A series of new 1,3-bis(1-adamantyl)propan-1,3-diones with a variably substituted phenyl ring at the C2 position was prepared either by the reaction of an appropriate Grignard reagent with adamatane-1-carbonyl chloride or by S E Ar on the unsubstituted 1,3-bis(1-adamantyl)-2-phenylpropan-1,3-dione. In addition to the single crystal X-ray diffraction analysis of three of the prepared compounds, the experimental 1 H and 13 C NMR, IR and Raman spectroscopic data were assigned and compared to those obtained by DFT computations. In the solid state, the syn -dioxo forms were exclusively observed, which are shown to also predominate in CHCl 3 solutions. The analysis of the Hirshfeld surface revealed that H⋯H and O⋯H contacts dominate the intermolecular interactions in the solid state, whereas π⋯π stacking plays a marginal role. [ABSTRACT FROM AUTHOR]

Tooeleite is an unique ferric arsenite sulfate mineral, which has the potential significance of directly fixing As(III) as mineral trap. The tooeleite and various precipitates were hydrothermally synthesized under the different of initial As(III)/As(V) molar ratios and characterized by XRD, FTIR, XPS and SEM. The crystallinity of tooeleite decreases with the amount of As(V). The precipitate is free of any crystalline tooeleite at the level of that XRD could detect when the ratio of As(III)/As(V) of 7:3 and more. The characteristic bands of tooeleite are observed in 772, 340, 696 and 304 cm −1 , which are assigned to the ν 1 , ν 2 , ν 3 and ν 4 vibrations of AsO 3 3− . These intensities of bands gradually decreases with the presence of As(V) and its increasing. An obviously wide band is observed in 830 cm −1 , which is the ν 1 vibration of AsO 4 . The result of XPS reveals that the binding energies of As 3d increase from 44.0 eV to 45.5 eV, which indicates that the amount of As(V) in the precipitates increases. The concentrations of arsenic released of these precipitates are 350–650 mg/L. The stability of tooeleite decreases by comparison when the presence of coexisting As(V) ions. [ABSTRACT FROM AUTHOR]

Aniline oligomers prepared via the oxidation of aniline under alkaline conditions at various concentrations of ammonia were carbonized at 650 °C in inert atmosphere. Subsequently, the prepared particles were mixed with silicone oil and the suspensions were used as electrorheological fluids. After the carbonization, when the higher amount of ammonia was present during the synthesis, the transition of morphology of the particles from microspheres to two-dimensional plates was observed. This transition led to a significant increase of viscosity of silicone-oil suspensions in the presence of external electric field, while their field-off viscosity remained nearly unchanged. Thus, the carbonization had the desired effect on the treated particles leading to extremely high electrorheological efficiency of the suspensions based on such particles. The highest electrorheological efficiency was achieved for the suspension based on carbonized particles prepared in 0.2 M ammonia. The dielectric spectroscopy was used as an evaluative tool of electrorheological performance of suspensions, and data correspond well with the obtained results from electrorheological experiments. [ABSTRACT FROM AUTHOR]

Abstract: Motivated by rather similar behavior of the Helmholtz capacitances of stepped Au(11n) and Ag(11n) electrodes we have extended a previous study on the vibration spectrum of water adsorbed at low temperatures on stepped gold surfaces to Ag(100), Ag(115) and Au(111) surfaces. On Ag(100) surfaces, the spectra show the presence of the typical H-bonded network of water molecules. The rather weak intensity, the absence of non-hydrogen bonded hydrogen atoms, the similarity to the infrared spectrum of ice crystallites, and the increase in the angular spread of the elastic peak are indicative of adsorption in form of three-dimensional clusters. This is stark contrast to Au(100) and Au(111) where the spectra match to a model involving stacks of water bilayers. The low coverage spectra on Ag(115) resemble the results on Au(115): A considerable fraction of the H-atoms remains in the non-H-bonded state and spectral features of water adsorbed at step-sites are identified. The first layer of water on Ag(115) surfaces should therefore have a similar structure as recently proposed in a theoretical study concerning water on Au(115). For larger doses, the experimental results on Ag(115) suggests the formation of three-dimensional clusters. This is contrary to Au(115) where the layered structure with a constant fraction of non-hydrogen-bonded H-atoms persists at higher doses. [Copyright &y& Elsevier]

Sejkoraite-(Y), the triclinic Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed., is a new member of the zippeite group from the Cervená vein, Jáchymov (Street Joachimsthal) ore district, Western Bohemia, Czech Republic. It grows on altered surface of relics of primary minerals: uraninite, chalcopyrite, and tennantite, and is associated with pseudojohannite, rabejacite, uranopilite, zippeite, and gypsum. Sejkoraite-(Y) forms crystalline aggregates consisting of yellow-orange to orange crystals, rarely up to 1 mm in diameter. The crystals have a strong vitreous luster and a pale yellow-to-yellow streak. The crystals are very brittle with perfect {100} cleavage and uneven fracture. The Mohs hardness is about 2. The mineral is not fluorescent either in short- or long-wavelength UV radiation. Sejkoraite-(Y) is yellow, with no visible pleochroism, biaxial negative with α' = 1.62(2), β' = 1.662(3), γ' = 1.73(1), 2Vcalc = 79°. The empirical chemical formula (mean of 8 electron microprobe point analyses) was calculated on the basis of 12 (S + U) atoms: Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. Sejkoraite-(Y) is triclinic, space group P1̄, a = 14.0743(6), b = 17.4174(7), c = 17.7062(8) Å, α = 75.933(4), β = 128.001(5), γ = 74.419(4)°, V = 2777.00(19) Å , Z = 2, Dcalc = 4.04 g/cm³. The seven strongest reflections in the X-ray powder diffraction pattern are [dobs in Å (I) (hkl)]: 9.28 (100) (100), 4.64 (39) (200), 3.631 (6) (1̄42), 3.451 (13) (1̄44), 3.385 (10) (24̅2), 3.292 (9) (044), 3.904(7) (300), 2.984 (10) (1̄4̄2). The crystal structure of sejkoraite-(Y) has been solved by the charge flipping method from single-crystal X-ray diffraction data and refined to Robs = 0.060 with GOFobs = 2.38, based on 6511 observed reflections. The crystal structure consists of uranyl sulfate sheets of zippeite anion topology, which alternate with an interlayer containing Y3+ (H2O)n polyhedra and uncoordinated H2O groups. Two yttrium atoms are linked to the sheet directly via uranyl oxygen atom, and the remaining one is bonded by hydrogen bonds only. In the Raman and infrared spectrum of sejkoraite-(Y) there are dominating stretching vibrations of SO4 tetrahedra (~1200-1100 cm-1), Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. stretching vibrations (~900-800 cm-1), and O-H stretching (~3500-3200 cm-1) and H-O-H bending modes (~1640 cm-1). The new mineral is named to honor Jiří Sejkora, a Czech mineralogist of the National Museum in Prague. [ABSTRACT FROM AUTHOR]

Abstract: The vibration spectrum of H2O (ice) adsorbed at low temperatures on Au(100), Au(111 1), and Au(11 5) is studied using electron energy loss spectroscopy. On the Au(100) surface, the spectra show the presence of the typical H-bonded network of water molecules for all coverages from the submonolayer into the multilayer range. The absence of a non-H-bonded OH-stretching mode is indicative for the “H-down bilayer”. On stepped surfaces, on the other hand, a considerable fraction of the H-atoms remains in the non-H-bonded state; surprisingly even in the multilayer range, and even after annealing. The fraction of non-H-bonded hydrogen atoms scales with the step density. Spectral features of water adsorbed at step-sites are isolated after annealing a surface exposed to small doses of H2O. The results are discussed in the context of recent theoretical studies as well as in conceivable relation to the experimentally found reduction of the Helmholtz-capacitance on stepped Au(11 n) electrodes. [Copyright &y& Elsevier]

Metakirchheimerite was found only on a few samples from the Jan Evangelista vein at the "Adit level" of the Svornost shaft, Jáchymov (St. Joachimsthal) ore district, Krušné Hory/Erzgebirge Mountains, Czech Republic. It forms rare crystalline aggregates consisting of fine tabular crystals reaching 0.1 mm in size, which are very brittle, having light pink to light orange colour, with a high vitreous lustre. Metakirchheimerite crystalline aggregates occur on carbonate gangue with disseminated primary minerals: arsenopyrite, uraninite and skutterudite. Studied metakirchheimerite is a (sub-)recent alteration product of the primary minerals, connected to the old open mine adit environment. According to electron microprobe analyses, the empirical formula of metakirchheimerite can be expressed, based on As + P = 2 apfu, as: (Co0.53Mg0.25Ni0.08Zn0.07Fe0.05Ca0.03)Σ1.01(UO2)2.07[(AsO4)1.99(PO4)0.01)]Σ2.00.8H2O. Metakirchheimerite from Jáchymov exhibits an extensive cationic substitution trend of the metanováčekite component. The X-ray diffraction pattern of metakirchheimerite is consistent with a triclinic symmetry inferred from the single-crystal study of the synthetic metakirchheimerite analogue. Refined unit-cell parameters for the triclinic space group P-1 are a 7.210(4) Å, b 9.771(6) Å, c 13.252(9) Å, α 75.39(4)°, β 83.94(6)°, γ 81.88(6)° with unit-cell volume V892(1)Å3. Both infrared and Raman spectra of metakirchheimerite exhibited stretching and bending vibrations of (UO2)2+, (AsO4)3, (PO4)3- and H2O groups. The vibration bands of all these units were tentatively assigned. The U-O bond lengths in uranyl and 0-H…O hydrogen bond lengths, which were inferred from the spectra, are consistent with published crystal structure data for a synthetic analogue of metakirchheimerite. [ABSTRACT FROM AUTHOR]

Abstract: UO2SO4·2.5H2O is monoclinic, space group P21/c (No. 14), unit-cell parameters of a =6.7260(1)Å, b =12.4210(2)Å, c =16.8270(3)Å, β =90.781(1)° with unit-cell volume V =1405.66(4)Å3, Z =8, D calc =3.84g/cm3. Two distinct uranium atoms, present as uranyl (UO2)2+, forming uranyl pentagonal bipyramids, two distinct sulfur atoms, forming sulfate tetrahedra and 17 oxygen atoms are present in the asymmetric part of its unit-cell. Two of oxygen atoms are water molecules bonded to the uranyl cation and one is water molecule bonded only by hydrogen-bonding. Crystal structure was refined fully anisotropically. Vibration modes of each molecular unit in Raman and infrared spectra were tentatively assigned and discussed, regarding refined structure. Inferred U–O lengths and hydrogen bond lengths are consistent with the crystal structure refinement. [Copyright &y& Elsevier]

Abstract: The polyhydridosiloxane was manufactured by sol–gel method from triethoxysilane. Methanol, hexane and water adsorption/desorption isotherms of the polyhydridosiloxane were measured at 293K and textural parameters were determined. Fourier transform infrared and inelastic neutron scattering spectroscopic examination of the polyhydridosiloxane along with the quantum chemical simulation have resulted in the theoretically grounded assignment of the spectral bands and evaluation of the theoretical model of the polyhydridosiloxane globule. [Copyright &y& Elsevier]

Abstract: Recent studies of molecules on surface by the use of tunneling electrons of scanning tunneling microscopy (STM) are reviewed. Characteristic features of tunneling current of STM are used not only for real space imaging with an atomic resolution but also are utilized for chemical analysis of a single molecule and manipulation of a molecule with controlled excitation of their vibration modes. As promising candidates of chemical analysis at a single molecule level, inelastic tunneling spectroscopy (IETS) researches are discussed. The mechanism of vibration excitation in STM-IETS is compared with that in high-resolution electron energy loss spectroscopy (HR-EELS). Successful observations of vibration modes of molecules such as C–H stretching mode are introduced. At the same time, expected increase of the importance of resonant scattering mechanism in STM-IETS compared with the conventional IETS is examined, whose mechanism assumes the trapping of tunneling electrons in the adsorbate resonant state and the formation of temporary negative ions. Next, applications of tunneling electrons to the manipulations of adsorbates are discussed focusing on the phenomena induced by vibrational excitations. STM has a unique character of high current density, which cannot be obtained with conventional sources. The similarity between the vibration excitation with the high current of STM and the phenomenon known as desorption induced by multielectron transfer (DIMET) are discussed. Surface phenomena such as desorption, hopping, rotation and chemical reactions are excited as a consequence of sequential climbing of ladders of a vibrational mode formed in the potential well. The intrinsic high current of STM tunneling current enables such multiple excitations in a more controllable manner than the use of photogenerated hot electrons, and is expected to make a contribution to the understanding of elemental processes of surface phenomena. [Copyright &y& Elsevier]

The As(V) adsorption onto gibbsite under different experimental conditions was examined. Macroscopic data suggests strong As(V) bonding on gibbsite possibly via a bidendate binuclear complexation mechanism. The As(V) adsorption was quantified with the charge distribution multi-site ions complexation (CD-MUSIC) model distributing the anion charge over 0- and 1-planes according to the modified Pauling''s bond valence theory. In the dual-adsorbates system of As(III) and As(V), the As(III) adsorption was predicted up to pH 8 utilizing the binding constants derived for single-adsorbate data. However, with pH > 8, the modeled As(III) adsorption data is overestimating the experimental values. [Copyright &y& Elsevier]

Natisite (Na2TiSiO5) is a layered sodium titanosilicate containing TiO5 square pyramids. The structure evolution of natisite in water and acid solutions is the basis for its potential applications. With Na2SiO3 as the silicon source, natisite with the shape of the square sheet was selectively prepared from the hydrothermal method with 14.3 mol/L NaOH solution at 240 °C. Natisite has 20 Raman active modes and 22 infrared active modes from the first-principles calculations within density functional theory, and the calculated Raman and infrared spectra agree well with the experimental ones. The characteristic Raman peak at 844 cm−1 is caused by the symmetric stretching of the apical Ti–O bond in the TiO5 unit, assigning to A1g and B2g modes. Natisite remains relatively stable in water with a sodium leaching percentage of lower than 6%. When washing with sulfuric acid solutions, the interlayer spacing of natisite is reduced due to the extensive removal of sodium ions, and an intermediate composed of SiO4 and newly formed TiO6 units may be formed. Moreover, after washing with water and acid solutions, 95.5%, 63.4%, and 35.2% of Na, Si, and Ti in natisite can be leached in total, respectively, resulting in the structural disintegration of natisite. [ABSTRACT FROM AUTHOR]

Abstract: X-ray fluorescence analysis using synchrotron radiation (SRXRF), X-ray powder diffraction, infrared and Raman spectroscopy had been applied for determination of microelemental and mineral composition of the kidney stones, gallstones and salivalities from natives of Novosibirsk and Novosibirsk region, Russia. The relationship between mineral, organic and microelemental composition of pathogenic calcilus was shown. [Copyright &y& Elsevier]