Shock-induced olivine-ringwoodite and plagioclase-maskelynite transformations in Bursa L6 chondrite: A Raman and ATR-FTIR spectroscopic study

Olivine-ringwoodite and plagioclase-maskelynite transformation mechanisms in the Bursa L6 chondrite were determined by Raman and Attenuated Total Reflectance (ATR)-Fourier Transform Infrared (FTIR) spectroscopic techniques. Forsterite composition was estimated to be 75% by using Raman and IR correlation data. Possible high impact shock pressure for Bursa meteorite was found to be at least 64.9 GPa. Besides, based on the olivine doublet (820 and 852 cm^-1) and Full Width at Half Maximum data (~20 and ~60 cm^-1, respectively) for maskelynite (509 and 580 cm^-1) observed in the Raman spectrum, we assigned the shock stage of this meteorite as at least S5, for the first time. Moreover, previously reported hypervelocity impact experiments also supported this assignment.

The interior and the fusion crust in Sariçiçek howardite: Study using X-ray diffraction, magnetization measurements and Mössbauer spectroscopy

The meteorite Sariçiçek, a 2015 howardite fall in Turkey, was analyzed using various physical techniques. Both the interior and the fusion crust were studied by optical and scanning electron microscopy with energy dispersive spectroscopy, X-ray diffraction, magnetization measurements and Mössbauer spectroscopy. The main and minor iron-bearing phases such as orthopyroxene, Ca-poor and Ca-rich clinopyroxene, chromite with hercynite, Fe²⁺ and Fe³⁺ ilmenite, troilite, α-Fe(Ni, Co), α₂-Fe(Ni, Co) and γ-Fe(Ni, Co) phases were identified. The ratios of Fe²⁺ occupancies in the M1 and M2 sites in the silicate phases as well as the equilibrium Fe²⁺ and Mg²⁺ cations distribution temperatures (T_eq) for orthopyroxene were estimated using X-ray diffraction and Mössbauer spectroscopy, which appeared to be in a good agreement: for example, T_eq were 886 and 878 K, respectively. The glass-like fusion crust of Sariçiçek consists of orthopyroxene with ferrous and ferric compounds that are likely products of combustion and melting.

The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation

Haumea-one of the four known trans-Neptunian dwarf planets-is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo's rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

Effects of hazardous pollutants on the walls of Valence Aqueduct (Istanbul) by Raman spectroscopy, SEM-EDX and Geographical Information System

This study involves Raman spectroscopic (176-2900cm(-1)), SEM-EDX and Geographical Information System studies of the pollutants on the walls of Valence Aqueduct (Bozdoğan Kemeri), Istanbul, Turkey. Raman spectroscopy is a useful analytical method in characterization of painting materials and corrosion products. Especially, when it is not possible to take the samples from the place they exist, handheld Raman spectrometers play an important role to identify the materials in these samples. Furthermore, more information could be gathered when it is combined with SEM-EDX studies. On the other hand, regarding the cultural heritage, it is crucial to determine precise coordinates of the historical peninsula and the samples which have been exposed to pollutants, by Geographical Information Systems in order to study them and take precautions for the future. Handheld Raman spectrometer (NanoRam by B&WTek) allows recording of acceptable and good quality spectra of a large majority of minerals outdoors. Raman spectra of minerals and pollutants in this study were obtained using 785nm laser excitation source. Observed Raman bands are found at correct wavenumber positions within ±3cm(-1) compared to reference values in the literature. Taking into account the resolution of the spectrometer (9cm(-1)), the results are still reliable and applicable on such systems. Areas of potential applications of these instruments include all kind of common geoscience work outdoors.

FT-IR spectroscopy and multivariate analysis as an auxiliary tool for diagnosis of mental disorders: Bipolar and schizophrenia cases

In this study, a methodology based on Fourier-transform infrared spectroscopy and principal component analysis and partial least square methods is proposed for the analysis of blood plasma samples in order to identify spectral changes correlated with some biomarkers associated with schizophrenia and bipolarity. Our main goal was to use the spectral information for the calibration of statistical models to discriminate and classify blood plasma samples belonging to bipolar and schizophrenic patients. IR spectra of 30 samples of blood plasma obtained from each, bipolar and schizophrenic patients and healthy control group were collected. The results obtained from principal component analysis (PCA) show a clear discrimination between the bipolar (BP), schizophrenic (SZ) and control group' (CG) blood samples that also give possibility to identify three main regions that show the major differences correlated with both mental disorders (biomarkers). Furthermore, a model for the classification of the blood samples was calibrated using partial least square discriminant analysis (PLS-DA), allowing the correct classification of BP, SZ and CG samples. The results obtained applying this methodology suggest that it can be used as a complimentary diagnostic tool for the detection and discrimination of these mental diseases.

Micro-Raman, mid-IR, far-IR and DFT studies on 2-[4-(4-fluorobenzamido)phenyl]benzothiazole

Molecular structure of 2-[4-(4-Fluorobenzamido)phenyl]benzothiazole was determined by quantum chemical calculations. MidIR and FarIR spectra were recorded at room temperature, with 4 cm(-1) resolution in the 4000-400 cm(-1) and 700-30 cm(-1) regions, respectively for the first time. Raman spectrum was recorded in the 4000-100 cm(-1) range. Optimized molecular structure and vibrational wavenumbers of the compound in its ground state have been calculated by using Density Functional Theory using B3LYP functional with 6-311++G(d,p) basis set. Vibrational wavenumbers were seen to be in good agreement with the experimental IR data. Furthermore, assignments of each vibrational mode were interpreted in terms of potential energy distributions in detail.

FT-IR spectral, DFT studies and detailed vibrational assignment on N,N',N"-tris(2-aminoethyl)-phosphoric acid triamide

Structure of N,N',N"-tris(2-aminoethyl)-phosphoric acid triamide (TEDAP), which is a phosphorus-containing reactive amine crosslinking agent and flame retardant material as well, identified by Fourier transform infrared (FT-IR) spectroscopy and quantum chemical calculations. The FT-IR spectrum of TEDAP, being a recently synthesized new compound, has been recorded in the 4000-650 cm(-1) region for the first time. The molecular geometry and vibrational wavenumbers of the compound in its ground state have been calculated by using Density Functional Theory (DFT) using B3LYP functional with 6-311++G(d,p) basis set. All calculations were performed with Gaussian09 software. The obtained vibrational wavenumbers and optimized geometric parameters were seen to be in good agreement with the experimental data. Furthermore, assignments of each vibrational mode were interpreted in terms of potential energy distributions (PED) in detail.

Micro-Raman, FTIR, SEM-EDX and structural analysis of the Çanakkale meteorite

This study demonstrates for the first time, the spectroscopic characterization of Çanakkale Meteorite that fell at Çanakkale, Republic of Turkey (40°8'44″N; 26°24'23″E). The olivine group [(Mg, Fe)(2)SiO(4)], enstatite [Mg(2)Si(2)O(6)] (one of the orthopyroxene minerals) and plagioclase were identified by the micro-Raman and FTIR spectroscopies and EDX-SEM analyses. This meteorite has not yet been classified in the World's Database of Meteorites. The aim of this study is to investigate this meteorite by vibrational spectroscopic techniques and open the possibility to classify it and list in the World's Database of Meteorites.

Structural conformations and vibrational spectral study of chloroflavone with density functional theoretical simulations

NIR-FT Raman and FT-IR spectra of 6-chloroflavone were recorded and analyzed. The vibrational wavenumber of the compound have been computed using B3LYP/6-31++G(d,p) level to derive the equilibrium geometry, conformational stability, molecular orbital energies and vibrational wavenumbers. The carbonyl stretching vibrations have been lowered due to conjugation and hydrogen bonding in the molecules. The assignment of fundamental vibrations agrees well with the calculated wavenumbers.