Search results for "SULFUR"

Resolving the forbidden band of SF6

2013

Sulfur hexafluoride is an important molecule for modeling thermophysical and polarizability properties. It is also a potent greenhouse gas of anthropogenic origin, whose concentration in the atmosphere, although very low is increasing rapidly; its global warming power is mostly conferred by its strong infrared absorption in the ν3 S-F stretching region near 948 cm(-1). This heavy species, however, features many hot bands at room temperature (at which only 31% of the molecules lie in the ground vibrational state), especially those originating from the lowest, v6 = 1 vibrational state. Unfortunately, the ν6 band itself (near 347 cm(-1)), in the first approximation, is both infrared- and Raman…

Sulfuric acid water table caves (Grotte du Chat / Acqua Fitusa /Bad Deutsch Altenburg + Kraushöhle).

2014

Sulfuric acid caves can display a variety of forms, from 3D maze systems, to isolated chambers, and more or less maze-like water table caves. Most of the voids are normally generated at or immediately above the water table, where condensation-corrosion processes are dominant, creating a set of characteristic meso- and micromorphologies. This paper deals with the description of four very typical sulfuric acid water table caves: the Grotte du Chat in Provence (France), the Acqua Fitusa Cave in Sicily (Italy), and the Bad Deutsch Altenburg and Kraushöhle caves in Austria.

Multiscale Investigation of the Structural, Electrical and Photoluminescence Properties of MoS2 Obtained by MoO3 Sulfurization

2022

In this paper, we report a multiscale investigation of the compositional, morphological, structural, electrical, and optical emission properties of 2H-MoS2 obtained by sulfurization at 800 °C of very thin MoO3 films (with thickness ranging from ~2.8 nm to ~4.2 nm) on a SiO2/Si substrate. XPS analyses confirmed that the sulfurization was very effective in the reduction of the oxide to MoS2, with only a small percentage of residual MoO3 present in the final film. High-resolution TEM/STEM analyses revealed the formation of few (i.e., 2–3 layers) of MoS2 nearly aligned with the SiO2 surface in the case of the thinnest (~2.8 nm) MoO3 film, whereas multilayers of MoS2 partially standing up with r…

Micrometer-size crystalline monolayer MoS2 domains obtained by sulfurization of molybdenum oxide ultrathin films

2023

In this work, the formation of micrometer-size crystalline monolayer (1L) MoS2 flakes with triangular shape and a central multilayer core is obtained by the sulfurization at 800 °C of pre-deposited ultrathin MoOx films (1.2–1.8 nm) on c-sapphire substrates. The thickness uniformity, crystalline quality, doping and strain distribution in the MoS2 flakes as a function of the initial MoOx thickness was evaluated by micro-Raman (μR) mapping. The excellent crystalline quality of the triangular 1L-MoS2 flakes was confirmed by micro-photoluminescence (μPL) maps, showing a very intense peak at ∼1.85 eV, that decreases in the central part, as expected for multilayers MoS2. A biaxial strain of ∼0.38–…

Deformation of sulfur hexafluoride and floppiness of trifluoromethyl sulfur pentafluoride

2006

International audience; With recent advances in space exploration and atmospheric chemistry there is an increased need for more spectroscopic tools to allow the of study complex species. One such tool is the theory of frame transformation of coupled rotor systems. In this article, the theory of frame transformation along with the concept of rotational energy surface is used to study the symmetry that occurs in trifluoromethyl sulfur pentafluoride due to the internal rotation of the CF3 radical and, more generally, to the extent of floppiness of SF5CF3. Other lower symmetries when a CF4 molecule is stuck on the various symmetry axes of an SF6 molecule are also discussed.

1991

Preparation des polymeres (CHR-CH 2 SO 2 ) (R=(CH 2 ) 9 N + Me 2 (CH 2 ) 3 SO 3 − , (CH 2 ) 8 CO[NC 4 H 8 N + (Me)([CH 2 ] 3 SO 3 − )] et R=CH 2 OCH 2 CHOHCH 2 N + Me(C 10 H 21 )(CH 2 ) 3 SO 3 − ) par copolymerisation spontanee des sels d'ammonium vinyliques correspondants avec SO 2 dans l'eau. Leurs proprietes de surface et de solubilisation de molecules hydrophobes en solution aqueuse sont caracteristiques de polysavons

Polythiophenes as markers of asphalt and archaeological tar pitch aging. Characterization using solid-state electrochemistry

2018

The voltammetry of immobilized microparticles (VIMP) was used to characterize organosulfur components from ovens found at the Spanish archaeological sites of Cueva de Nerja (ca. 35,000cal BC), la Illeta dels Banyets (4th century BCE) and Gestalgar (12th–13th CE), and asphalt probes subjected to PAV and SUNTEST aging protocols. The voltammetric responses of the archaeological samples and the asphalt probes after photodegradation were quite similar, indicating the presence of polythiophene components which could act as age/degradation markers. Keywords: Voltammetry, Archaeology, Asphalt, Tar pitch, Organosulfur compounds

ChemInform Abstract: The Valence States of Nickel, Tin, and Sulfur in the Ternary Chalcogenide Ni3Sn2S2 - XPS, 61Ni and 119Sn Moessbauer Investigatio…

2010

Sulfur isotope ratio measurements of individual sulfate particles by NanoSIMS

2008

Abstract The sulfur isotopic compositions of barite (BaSO4), anhydrite (CaSO4), gypsum (CaSO4·2H2O), mascagnite ((NH4)2SO4), thenardite (Na2SO4), boetite (K2SO4), epsomite (MgSO4·7H2O), magnesium sulfate (MgSO4·xH2O) and cysteine (an amino acid) were determined with a Cameca NanoSIMS 50 ion microprobe employing a Cs+ primary ion beam and measuring negative secondary ions. This ion microprobe permits the analysis of sulfur isotope ratios in sulfates on 0.001–0.5 ng of sample material, enabling the analysis of individual S-bearing particles with diameters as small as 500 nm. The grain-to-grain reproducibility of measurements is typically 5‰ (1σ) for micron-sized grains,

IR fingerprints of U(VI) nitrate monoamides complexes: a joint experimental and theoretical study.

2010

Infrared spectra of 0.5 mol·L-1 uranium(VI) nitrate monoamide complexes in toluene have been recorded and compared with infrared spectra calculated by DFT. The investigated monoamides were N,N- dimethylformamide (DMF), N,N-dibutylformamide (DBF), and N,N- dicyclohexylformamide (DcHF). The validity of DFT calculations for describing uranium nitrate monoamide complexes has been confirmed as a fair agreement between experimental and calculated spectra was obtained. Furthermore, a topological analysis of the electron density has been carried out to characterize monoamide-uranium interactions. From this work, it appears that the increase of stability of uranylmonoamide complexes may be directly …