In Situ IR Transmission Spectroscopic Observation and Kinetic Analyses of Initial Stage of the Maillard Reaction as a Simulated Formation Process of Humic Substances

The nucleation and initial stage of Pd2Si crystals on Si(111) surface is studied in situ using an Ultra-High Vacuum (UHV) Transmission Electron Microscope (TEM). A modified JEOL 200CX TEM is used for the study. The Si(111) sample is prepared by chemical thinning and is cleaned inside the UHV chamber with base pressure of 1x10−9 τ. A Pd film of 20 Å thick is deposited on to the Si(111) sample in situ using a built-in mini evaporator. This room temperature deposited Pd film is thermally annealed subsequently to form Pd2Si crystals. Surface sensitive dark field imaging is used for the study to reveal the effect of surface and interface steps.The initial growth of the Pd2Si has three stages: nucleation, growth of the nuclei and coalescence of the nuclei. Our experiments shows that the nucleation of the Pd2Si crystal occurs randomly and almost instantaneously on the terraces upon thermal annealing or electron irradiation.

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An Atmospheric Origin for HCN-Derived Polymers on Titan

Processes ◽

10.3390/pr9060965 ◽

2021 ◽

Vol 9 (6) ◽

pp. 965

Author(s):

Zoé Perrin ◽

Nathalie Carrasco ◽

Audrey Chatain ◽

Lora Jovanovic ◽

Ludovic Vettier ◽

...

Keyword(s):

Chemical Composition ◽

Gas Phase ◽

Formation Process ◽

Upper Atmosphere ◽

Gas Mixture ◽

Space Probe ◽

Atmospheric Haze ◽

Formation And Evolution ◽

Haze Formation

Titan’s haze is strongly suspected to be an HCN-derived polymer, but despite the first in situ measurements by the ESA-Huygens space probe, its chemical composition and formation process remain largely unknown. To investigate this question, we simulated the atmospheric haze formation process, experimentally. We synthesized analogues of Titan’s haze, named Titan tholins, in an irradiated N2–CH4 gas mixture, mimicking Titan’s upper atmosphere chemistry. HCN was monitored in situ in the gas phase simultaneously with the formation and evolution of the haze particles. We show that HCN is produced as long as the particles are absent, and is then progressively consumed when the particles appear and grow. This work highlights HCN as an effective precursor of Titan’s haze and confirms the HCN-derived polymer nature of the haze.

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In Situ IR Spectroscopy for Following the Copolymerization of CO2and Epoxides

Chemie Ingenieur Technik ◽

10.1002/cite.201450648 ◽

2014 ◽

Vol 86 (9) ◽

pp. 1627-1628

Author(s):

K. Böhm ◽

W. Leitner ◽

T. E. Müller

Keyword(s):

Ir Spectroscopy ◽

In Situ Ir ◽

In Situ Ir Spectroscopy

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ChemInform Abstract: An in situ IR Spectroscopic Study of the Anodic Oxide Film on Cobalt in Alkaline Solutions.

ChemInform ◽

10.1002/chin.199246018 ◽

2010 ◽

Vol 23 (46) ◽

pp. no-no

Author(s):

A. BEWICK ◽

C. GUTIERREZ ◽

G. LARRAMONA

Keyword(s):

Oxide Film ◽

Spectroscopic Study ◽

Anodic Oxide ◽

Anodic Oxide Film ◽

Alkaline Solutions ◽

In Situ Ir ◽

Ir Spectroscopic

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In-Situ Characterization of Growth and Intermixing at a Heteroepitaxial Interface: Fe on Au(001)

MRS Proceedings ◽

10.1557/proc-318-13 ◽

1993 ◽

Vol 318 ◽

Author(s):

Q. Jiang ◽

A. Chan ◽

Y.-L. He ◽

G.-C. Wang

Keyword(s):

Elevated Temperatures ◽

Chemical Elements ◽

Background Intensity ◽

In Situ Characterization ◽

Initial Stage ◽

Monolayer Growth ◽

Low Energy Electron ◽

Energy Dependent

ABSTRACTThe growth and chemical intermixing of submonolayer and a few monolayer thick Fe films on a Au(001) surface was studied by High Resolution Low Energy Electron Diffraction (HRLEED) technique. Through the analysis of the energy dependent angular profiles as a function of time, we obtained the distribution of islands and distribution of spacings during submonolayer growth. The interference of electron waves from different chemical elements in terraces at different heights in the surface contributes to the background intensity and broadening in the angular profiles of diffraction beams. A subsurface Fe capped by Au islands as a result of atomic place exchange was observed at the initial stage of monolayer growth. From the energy dependent angular profiles as a function of temperature, we determine the quantitative change of inhomogeneity length (∼20 Å) at the interface of ultrathin films at elevated temperatures due to intermixing.

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In situ Raman Spectroscopic Observation of Polymer Chains in Semi-Crystalline Polyethylene Solids

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2020-1618 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Yusuke Hiejima ◽

Takumitsu Kida ◽

Koh-hei Nitta

Keyword(s):

Conformational Changes ◽

Tensile Elongation ◽

Spectroscopic Observation ◽

Polymer Chains ◽

Trans Conformation ◽

Raman Spectroscopic ◽

Higher Temperature ◽

Microscopic Origin ◽

Crystalline Polyethylene

AbstractIn situ Raman spectroscopy is applied for polyethylene solid under various environments to elucidate the morphological and conformational changes. The trans conformation retains up to higher temperature for high-density polyethylene, reflecting higher stability of the orthorhombic crystals composed of stacked trans chains. It is suggested that the conversion of the non-crystalline trans chains to the crystalline phase is the microscopic origin of thermal history in the crystallinity, whereas the transformation between the trans and gauche conformers is practically in thermal equilibrium. Microscopic and dynamic mechanism of deformation during uniaxial stretching is investigated for the molecular orientation and the microscopic load sharing on the crystalline and amorphous chains. Lower crystallinity results in smoother and higher orientation toward the stretching direction, as well as higher load on the amorphous chains, during tensile elongation.

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In situ IR observation of photo-chemically deposited silicon nitride thin films

Applied Surface Science ◽

10.1016/0169-4332(91)90365-q ◽

1991 ◽

Vol 48-49 ◽

pp. 409-413 ◽

Cited By ~ 5

Author(s):

T. Wadayama ◽

T. Hihara ◽

A. Hatta ◽

W. Suëtaka

Keyword(s):

Thin Films ◽

Silicon Nitride ◽

In Situ Ir

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Incorporation and Role of Nitrogen During Oxynitridation of Silicon Studied by Photoelectron Spectroscopy

MRS Proceedings ◽

10.1557/proc-567-51 ◽

1999 ◽

Vol 567 ◽

Cited By ~ 1

Author(s):

Masayuki Suzuki ◽

Yoji Saito

Keyword(s):

Photoelectron Spectroscopy ◽

High Vacuum ◽

Oxide Films ◽

Silicon Surfaces ◽

Gaseous Mixtures ◽

X Ray ◽

Initial Stage ◽

Thermal Stability Of

ABSTRACTWe tried direct oxynitridation of silicon surfaces by remote-plasma-exited nitrogen and oxygen gaseous mixtures at 700°C in a high vacuum. The oxynitrided surfaces were investigated with in-situ X-ray photoelectron spectroscopy. With increase of the oxynitridation time, the surface density of nitrogen gradually increases, but that of oxygen shows nearly saturation behavior after the rapid increase in the initial stage. We also annealed the grown oxynitride and oxide films to investigate the role of the contained nitrogen. The desorption rate of oxygen from the oxynitride films is much less than that from oxide films. We confirmed that nitrogen stabilizes the thermal stability of these oxynitride films.

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