Organic chemistry of NH₃ and HCN induced by an atmospheric abnormal glow discharge in N₂-CH₄ mixtures

The formation of the chemical products produced in an atmospheric glow discharge fed by a N2-CH4 gas mixture has been studied using Fourier Transform InfraRed (FTIR) and Optical Emission Spectrometry (OES). The measurements were carried out in a flowing regime at ambient temperature and pressure with CH4 concentrations ranging from 0.5% to 2%. In the recorded emission spectra the lines of the second positive system CN system and the first negative system of N2 were found to be the most intensive but atomic Hα, Hβ, and C (247 nm) lines were also observed. FTIR-measurements revealed HCN and NH3 to be the major products of the plasma with traces of C2H2. These same molecules have been detected in Titan's atmosphere and the present experiments may provide some novel insights into the chemical and physical mechanisms prevalent in Titan's atmosphere with these smaller species believed to be the precursors of heavier organic species in Titan's atmosphere and on its surface

Optical Diagnostics of RF Argon and Xenon Magnetron Discharges

A comparison of magnetron discharges in Ar and Xe gases with Al and BN targets has shown that a similar electron kinetic is producing about the same quantity of Ar and Xe metastable atoms: $(1{-}3) \times 10^{10}$ cm$^{-3}$ at gas pressures of 25 and 100 mTorr and RF powers, W, from 5 to 50 watts. The electron density is varying as $W^{\frac{1}{2}}$ in the two gases. The sputtering yields of Al and BN targets are lower in Xe than in Ar, by factors of 1.1–1.2 for Al and of 3 for BN.La comparaison de décharges magnétrons dans des gaz d'argon et de xénon, avec des cibles en Al et BN indique que des quantités équivalentes d'argon et de xénon métastables sont produites, à savoir $(1{-}3) \times 10^{10}$ cm$^{-3}$ à des pressions de 25 et 100 mTorr et des puissances RF, W, de 5 à 50 watts. La densité électronique varie comme $W^{\frac{1}{2}}$ dans les deux cas. Les taux de pulvérisation de cibles d'Al et de BN sont plus faibles dans le Xe que dans l'Ar, d'un facteur 1, 1– 1, 2 pour Al et 3 pour BN

Precisely controlled fabrication, manipulation and in-situ analysis of Cu based nanoparticles

13 pags., 8 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0The increasing demand for nanostructured materials is mainly motivated by their key role in a wide variety of technologically relevant fields such as biomedicine, green sustainable energy or catalysis. We have succeeded to scale-up a type of gas aggregation source, called a multiple ion cluster source, for the generation of complex, ultra-pure nanoparticles made of different materials. The high production rates achieved (tens of g/day) for this kind of gas aggregation sources, and the inherent ability to control the structure of the nanoparticles in a controlled environment, make this equipment appealing for industrial purposes, a highly coveted aspect since the introduction of this type of sources. Furthermore, our innovative UHV experimental station also includes in-flight manipulation and processing capabilities by annealing, acceleration, or interaction with background gases along with in-situ characterization of the clusters and nanoparticles fabricated. As an example to demonstrate some of the capabilities of this new equipment, herein we present the fabrication of copper nanoparticles and their processing, including the controlled oxidation (from Cu to CuO through CuO, and their mixtures) at different stages in the machine.This work was supported by the European Union [grant number ERC-2013-SyG 610256 NANOCOSMOS]; the Spanish MINECO [grant numbers MAT2017-85089-C2-1-R, MAT2014-54231-C4-1-P, MAT2014-54231- C4-4-P, MAT2014-59772-C2-2-P, FIS2016-77578-R, FIS2013-48087-C2-1P, FIS2016-77726-C3-1P and CSIC13-4E-1775].Peer Reviewe