Vacuum Apparatus

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Dulieu François - One of the best experts on this subject based on the ideXlab platform.

  • VENUS: a new Apparatus to investigate surface chemistry routes leading to complex organic molecules in space
    2020
    Co-Authors: Congiu Emanuele, Sow Abdellahi, Nguyen Thanh, Baouche Saoud, Dulieu François
    Abstract:

    A multi-beam ultra-high Vacuum Apparatus is presented. In this article we describe the design and construction of a new laboratory astrophysics experiment -- VErs de NoUvelles Synth\`eses (VENUS) -- that recreates the solid-state non-energetic formation conditions of complex organic molecules in dark clouds and circumstellar environments. The novel implementation of four operational differentially-pumped beam lines will be used to determine the feasibility and the rates for the various reactions that contribute to formation of molecules containing more than six atoms. Data are collected by means of Fourier transform infrared spectroscopy and quadrupole mass spectrometry. The gold-coated sample holder reaches temperatures between 7 and 400 K. The Apparatus was carefully calibrated and the acquisition system was developed to ensure that experimental parameters are recorded as accurately as possible. A great effort has been made to have the beam lines converge towards the sample. Experiments have been developed to check the beam alignment using reacting systems of neutral species (NH$_3$, H$_2$CO). Preliminary original results were obtained for the NO+H system, which shows that chemistry occurs only in the very first outer layer of the deposited species, that is the chemical layer and the physical layer coincide. This article illustrates the characteristics, performance, and future potential of the new Apparatus in view of the forthcoming launch of the James Webb Space Telescope. We show that VENUS will have a major impact through its contributions to surface science and astrochemistry.Comment: 35 pages, 18 figure

  • A new multi-beam Apparatus for the study of surface chemistry routes to formation of complex organic molecules in space
    'AIP Publishing', 2020
    Co-Authors: Congiu Emanuele, Sow Abdellahi, Nguyen Thanh, Baouche Saoud, Dulieu François
    Abstract:

    Promoted as an Editor's Pick by the RSI EditorsA multi-beam ultra-high Vacuum Apparatus is presented. In this article we describe the design and construction of a new laboratory astrophysics experiment -- VErs de NoUvelles Synth\`eses (VENUS) -- that recreates the solid-state non-energetic formation conditions of complex organic molecules in dark clouds and circumstellar environments. The novel implementation of four operational differentially-pumped beam lines will be used to determine the feasibility and the rates for the various reactions that contribute to formation of molecules containing more than six atoms. Data are collected by means of Fourier transform infrared spectroscopy and quadrupole mass spectrometry. The gold-coated sample holder reaches temperatures between 7 and 400 K. The Apparatus was carefully calibrated and the acquisition system was developed to ensure that experimental parameters are recorded as accurately as possible. A great effort has been made to have the beam lines converge towards the sample. Experiments have been developed to check the beam alignment using reacting systems of neutral species (NH$_3$, H$_2$CO). Preliminary original results were obtained for the NO+H system, which shows that chemistry occurs only in the very first outer layer of the deposited species, that is the chemical layer and the physical layer coincide. This article illustrates the characteristics, performance, and future potential of the new Apparatus in view of the forthcoming launch of the James Webb Space Telescope. We show that VENUS will have a major impact through its contributions to surface science and astrochemistry

  • A new multi-beam Apparatus for the study of surface chemistry routes to formation of complex organic molecules in space
    'AIP Publishing', 2020
    Co-Authors: Congiu Emanuele, Sow Abdellahi, Nguyen Thanh, Baouche Saoud, Dulieu François
    Abstract:

    A multi-beam ultra-high Vacuum Apparatus is presented. In this article we describe the design and construction of a new laboratory astrophysics experiment -- VErs de NoUvelles Synth\`eses (VENUS) -- that recreates the solid-state non-energetic formation conditions of complex organic molecules in dark clouds and circumstellar environments. The novel implementation of four operational differentially-pumped beam lines will be used to determine the feasibility and the rates for the various reactions that contribute to formation of molecules containing more than six atoms. Data are collected by means of Fourier transform infrared spectroscopy and quadrupole mass spectrometry. The gold-coated sample holder reaches temperatures between 7 and 400 K. The Apparatus was carefully calibrated and the acquisition system was developed to ensure that experimental parameters are recorded as accurately as possible. A great effort has been made to have the beam lines converge towards the sample. Experiments have been developed to check the beam alignment using reacting systems of neutral species (NH$_3$, H$_2$CO). Preliminary original results were obtained for the NO+H system, which shows that chemistry occurs only in the very first outer layer of the deposited species, that is the chemical layer and the physical layer coincide. This article illustrates the characteristics, performance, and future potential of the new Apparatus in view of the forthcoming launch of the James Webb Space Telescope. We show that VENUS will have a major impact through its contributions to surface science and astrochemistry.Comment: Promoted as an Editor's Pick by the RSI Editor

I P Prosvirin - One of the best experts on this subject based on the ideXlab platform.

  • x ray photoelectron spectroscopy for investigation of heterogeneous catalytic processes
    Advances in Catalysis, 2009
    Co-Authors: Axel Knopgericke, Evgueni Kleimenov, Michael Havecker, Raoul Blume, Detre Teschner, Spiros Zafeiratos, Robert Schlogl, Valerii I Bukhtiyarov, Vasiliy V Kaichev, I P Prosvirin
    Abstract:

    Abstract X‐ray photoelectron spectroscopy (XPS) is commonly applied for the characterization of surfaces in ultrahigh Vacuum Apparatus, but the application of XPS at elevated pressures has been known for more than 35 years. This chapter is a description of the development of XPS as a novel method to characterize surfaces of catalysts under reaction conditions. This technique offers opportunities for determination of correlations between the electronic surface structures of active catalysts and the catalytic activity, which can be characterized simultaneously by analysis of gas‐phase products. Apparatus used for XPS investigations of samples in reactive atmospheres is described here; the application of synchrotron radiation allows the determination of depth profiles in the catalyst, made possible by changes in the photon energy. The methods are illustrated with examples including methanol oxidation on copper and ethene epoxidation on silver. Correlations between the abundance of surface oxygen species and yields of selective oxidation products are presented in detail. Further examples include CO adsorption and methanol decomposition on palladium and CO oxidation on ruthenium.

Masaaki Iiyama - One of the best experts on this subject based on the ideXlab platform.

Peter H Mcmurry - One of the best experts on this subject based on the ideXlab platform.

  • spatial distribution of chemical components in aerosol particles as determined from secondary electron yield measurements implications for mechanisms of multicomponent aerosol crystallization
    Journal of Colloid and Interface Science, 1997
    Co-Authors: P Ziemann, Peter H Mcmurry
    Abstract:

    Abstract Secondary electron yield measurements were used to determine the distribution of chemical components in multicomponent aerosol particles formed by crystallization from aqueous solution droplets. Yield measurements were made by measuring the charge acquired by a beam of particles as they passed through an electron beam (100–600 eV energy) inside a high-Vacuum Apparatus. Yields were sufficiently different for certain compounds that measurements made on two-component particles could be used to obtain information on the spatial distribution of components. Variations in chemical composition as a function of depth beneath the particle surface were ascertained from the energy dependence of the measured yields, since the electron penetration depth, and therefore the probe depth, increases with electron energy. The results for mixed NaCl–NH 4 Cl particles indicate that the distribution of components within these particles is relatively homogeneous, while measurements made on mixed NaCl–NaNO 3 particles are indicative of particles having a heterogeneous core–shell morphology. Results for mixed Na 2 SO 4 –(NH 4 ) 2 SO 4 particles are ambiguous, probably because of the complexity of the phase diagram of this system. It appears that the mechanism by which aerosol particles crystallize, and therefore the resulting distribution of chemical components within particles, is strongly dependent on particle composition and environmental variables.

Congiu Emanuele - One of the best experts on this subject based on the ideXlab platform.

  • VENUS: a new Apparatus to investigate surface chemistry routes leading to complex organic molecules in space
    2020
    Co-Authors: Congiu Emanuele, Sow Abdellahi, Nguyen Thanh, Baouche Saoud, Dulieu François
    Abstract:

    A multi-beam ultra-high Vacuum Apparatus is presented. In this article we describe the design and construction of a new laboratory astrophysics experiment -- VErs de NoUvelles Synth\`eses (VENUS) -- that recreates the solid-state non-energetic formation conditions of complex organic molecules in dark clouds and circumstellar environments. The novel implementation of four operational differentially-pumped beam lines will be used to determine the feasibility and the rates for the various reactions that contribute to formation of molecules containing more than six atoms. Data are collected by means of Fourier transform infrared spectroscopy and quadrupole mass spectrometry. The gold-coated sample holder reaches temperatures between 7 and 400 K. The Apparatus was carefully calibrated and the acquisition system was developed to ensure that experimental parameters are recorded as accurately as possible. A great effort has been made to have the beam lines converge towards the sample. Experiments have been developed to check the beam alignment using reacting systems of neutral species (NH$_3$, H$_2$CO). Preliminary original results were obtained for the NO+H system, which shows that chemistry occurs only in the very first outer layer of the deposited species, that is the chemical layer and the physical layer coincide. This article illustrates the characteristics, performance, and future potential of the new Apparatus in view of the forthcoming launch of the James Webb Space Telescope. We show that VENUS will have a major impact through its contributions to surface science and astrochemistry.Comment: 35 pages, 18 figure

  • A new multi-beam Apparatus for the study of surface chemistry routes to formation of complex organic molecules in space
    'AIP Publishing', 2020
    Co-Authors: Congiu Emanuele, Sow Abdellahi, Nguyen Thanh, Baouche Saoud, Dulieu François
    Abstract:

    Promoted as an Editor's Pick by the RSI EditorsA multi-beam ultra-high Vacuum Apparatus is presented. In this article we describe the design and construction of a new laboratory astrophysics experiment -- VErs de NoUvelles Synth\`eses (VENUS) -- that recreates the solid-state non-energetic formation conditions of complex organic molecules in dark clouds and circumstellar environments. The novel implementation of four operational differentially-pumped beam lines will be used to determine the feasibility and the rates for the various reactions that contribute to formation of molecules containing more than six atoms. Data are collected by means of Fourier transform infrared spectroscopy and quadrupole mass spectrometry. The gold-coated sample holder reaches temperatures between 7 and 400 K. The Apparatus was carefully calibrated and the acquisition system was developed to ensure that experimental parameters are recorded as accurately as possible. A great effort has been made to have the beam lines converge towards the sample. Experiments have been developed to check the beam alignment using reacting systems of neutral species (NH$_3$, H$_2$CO). Preliminary original results were obtained for the NO+H system, which shows that chemistry occurs only in the very first outer layer of the deposited species, that is the chemical layer and the physical layer coincide. This article illustrates the characteristics, performance, and future potential of the new Apparatus in view of the forthcoming launch of the James Webb Space Telescope. We show that VENUS will have a major impact through its contributions to surface science and astrochemistry

  • A new multi-beam Apparatus for the study of surface chemistry routes to formation of complex organic molecules in space
    'AIP Publishing', 2020
    Co-Authors: Congiu Emanuele, Sow Abdellahi, Nguyen Thanh, Baouche Saoud, Dulieu François
    Abstract:

    A multi-beam ultra-high Vacuum Apparatus is presented. In this article we describe the design and construction of a new laboratory astrophysics experiment -- VErs de NoUvelles Synth\`eses (VENUS) -- that recreates the solid-state non-energetic formation conditions of complex organic molecules in dark clouds and circumstellar environments. The novel implementation of four operational differentially-pumped beam lines will be used to determine the feasibility and the rates for the various reactions that contribute to formation of molecules containing more than six atoms. Data are collected by means of Fourier transform infrared spectroscopy and quadrupole mass spectrometry. The gold-coated sample holder reaches temperatures between 7 and 400 K. The Apparatus was carefully calibrated and the acquisition system was developed to ensure that experimental parameters are recorded as accurately as possible. A great effort has been made to have the beam lines converge towards the sample. Experiments have been developed to check the beam alignment using reacting systems of neutral species (NH$_3$, H$_2$CO). Preliminary original results were obtained for the NO+H system, which shows that chemistry occurs only in the very first outer layer of the deposited species, that is the chemical layer and the physical layer coincide. This article illustrates the characteristics, performance, and future potential of the new Apparatus in view of the forthcoming launch of the James Webb Space Telescope. We show that VENUS will have a major impact through its contributions to surface science and astrochemistry.Comment: Promoted as an Editor's Pick by the RSI Editor