The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Régis Bisson - One of the best experts on this subject based on the ideXlab platform.
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Sticking Probability of Ammonia Molecules on Tungsten and 316L Stainless Steel Surfaces
The Journal of Physical Chemistry C, 2020Co-Authors: Marco Minissale, J.-b. Faure, A. Dunand, Thierry Angot, G. De Temmerman, Régis BissonAbstract:We present measurements of the Sticking Probability of ammonia on two metals, tungsten and 316L stainless steel, covered with natural surface impurities as they will be used for the international n...
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The Sticking Probability of D2O-water on ice: Isotope effects and the influence of vibrational excitation
Journal of Chemical Physics, 2012Co-Authors: P. Morten Hundt, Régis Bisson, Rainer D. BeckAbstract:The present study measures the Sticking Probability of heavy water (D2O) on H2O- and on D2O-ice and probes the influence of selective OD-stretch excitation on D2O Sticking on these ices. Molecular beam techniques are combined with infrared laser excitation to allow for precise control of incident angle, translational energy, and vibrational state of the incident molecules. For a translational energy of 69 kJ/mol and large incident angles (θ ≥ 45°), the Sticking Probability of D2O on H2O-ice was found to be 1% lower than on D2O-ice. OD-stretch excitation by IR laser pumping of the incident D2O molecules produces no detectable change of the D2O Sticking Probability (
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the Sticking Probability of d2o water on ice isotope effects and the influence of vibrational excitation
Journal of Chemical Physics, 2012Co-Authors: Morten P Hundt, Régis Bisson, Rainer D. BeckAbstract:The present study measures the Sticking Probability of heavy water (D2O) on H2O- and on D2O-ice and probes the influence of selective OD-stretch excitation on D2O Sticking on these ices. Molecular beam techniques are combined with infrared laser excitation to allow for precise control of incident angle, translational energy, and vibrational state of the incident molecules. For a translational energy of 69 kJ/mol and large incident angles (θ ≥ 45°), the Sticking Probability of D2O on H2O-ice was found to be 1% lower than on D2O-ice. OD-stretch excitation by IR laser pumping of the incident D2O molecules produces no detectable change of the D2O Sticking Probability (<10−3). The results are compared with other gas/surface systems for which the effect of vibrational excitation on trapping has been probed experimentally.
Haruhiko Ito - One of the best experts on this subject based on the ideXlab platform.
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Sticking Probability of CN radicals
Diamond and Related Materials, 2011Co-Authors: Haruhiko Ito, Hitoshi Araki, Akira WadaAbstract:Abstract The Sticking Probability, s, of CN(X2Σ+) radicals which were the precursor of the formation of amorphous carbon nitride films with high [N]/([N]+[C]) ratios (≤ 0.5) was re-evaluated. CN(X2Σ+) radicals were generated from the decomposition of BrCN with the microwave discharge flow of Ar of the pressure of 0.2–0.4 Torr. The number density of CN(X2Σ+), nCN(X), was evaluated from the intensity of the CN(A2Πi–X2Σ+) laser-induced fluorescence spectrum calibrated against Rayleigh scattering intensity of Ar. The weight of the C and N components of films, w, was evaluated from the compositional analysis for the deposited films using Rutherford back scattering and elastic recoil detection analysis. The [N]/([N]+[C]) ratios of films were 0.4–0.5. Based on nCN(X), w, and the flow speed measured by a time-resolved emission, s was evaluated both under the desiccated and H2O-added conditions as (8.5 ± 2.1) × 10− 2 − (6.1 ± 1.2) × 10− 2 and (11.4 ± 1.3) × 10− 2 − (7.4 ± 1.8) × 10− 2, respectively. The variation of s under various experimental conditions was discussed based on the electron densities in the reaction region.
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Measurements of density and Sticking Probability of CN(X2Σ+) radicals by laser-induced fluorescence spectroscopy
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2006Co-Authors: Haruhiko Ito, Kouichi Oda, Yoshinori Kawamura, Hidetoshi SaitohAbstract:CN(X2Σ+) radicals were produced by the decomposition of BrCN with the microwave discharge flow of Ar under the conditions of Ar pressure in the range of 0.40–0.70 Torr. The laser-induced fluorescence (LIF) spectra of the CN(A2Πi–X2Σ+), 4–0, 5–1, and 7–2 bands were observed, and their intensities were calibrated against Rayleigh-scattering intensity by Ar atoms, from which the CN(X2Σ+) radical density (nCN(X)) was determined as (0.67 ± 0.25) × 1018 to (4.42 ± 0.83) × 1018 m−3. Hydrogenated amorphous carbon nitride (a-CNx:H) films were formed by depositing the CN(X2Σ+) radicals on Si substrates in the same reaction system as LIF. The Sticking Probability (s) of the CN(X2Σ+) radicals onto the a-CNx:H films was determined by using nCN(X), the flow speed, and the weight (w) of a-CNx:H. The s value was determined as (6.4 ± 6.4) × 10−2 to (2.5 ± 1.2) × 10−2, where the errors are predominantly determined by those in nCN(X) and w. The procedure described in the present study will provide a methodology to determine the Sticking Probability of the precursor radicals of the film formation based on the gas-phase LIF spectroscopy.
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Sticking Probability of the cn x2σ radicals onto the hydrogenated amorphous carbon nitride films
Thin Solid Films, 2006Co-Authors: Haruhiko Ito, Kouichi Oda, Hidetoshi SaitohAbstract:The Sticking Probability (s) of the CN(X 2 Σ + ) radicals onto the hydrogenated amorphous carbon nitride (a-CN x :H) films was determined by measuring the density of CN(X 2 Σ + ) in the gas phase, the flow speed, and the weight of a-CN x :H. The CN(X 2 Σ + ) radicals were produced by the dissociative excitation reaction of BrCN with the microwave discharge flow of Ar, and were observed by the laser induced fluorescence (LIF) spectroscopy of the CN(A 2 Π t -X 2 Σ + ), 4-0, 5-1, and 7-2 bands. The LIF intensity was calibrated against Rayleigh scattering intensity by Ar atoms, from which the density of CN(X 2 Σ + ) was determined as 1.0 x 10 18 -4.9 × 10 18 m -3 depending on the pressure of Ar (P Ar ) as 0.4-0.7 Torr. The s value was in the range of 0.032-0.019 which was also dependent on P Ar . According to the IR observation of the a-CN x :H films, the P Ar -dependence of s was found to originate in the reactivity of the CN radicals on the film surface.
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absolute density and Sticking Probability of the cn x2σ radicals produced by the dissociative excitation reaction of brcn with the microwave discharge flow of ar
Japanese Journal of Applied Physics, 2003Co-Authors: Haruhiko Ito, Shinya Ichimura, Keiichi Namiki, Hidetoshi SaitohAbstract:The 4-0, 5-1, and 7-2 bands of the A2Πi–X2Σ+ transition of the CN radical produced by the dissociative excitation reaction of BrCN with the microwave discharge flow of Ar were observed by laser induced fluorescence (LIF) spectroscopy. The intensity of the LIF spectrum of the individual transition was evaluated by a spectral simulation analysis, and converted to the absolute value by calibrating against Rayleigh scattering by Ar atoms. The effective lifetime of the A2Πi state was measured to be 2.2(5) µs. The absolute number density of the CN(X2Σ+) radicals in the observation region of LIF was evaluated to be 1.5(3)×1020 m-3. Based on this value, the pumping speed, and the amount of a-CNx:H film deposited, the Sticking Probability of the CN radicals onto the a-CNx:H films was estimated to be 0.01.
Eli Pollak - One of the best experts on this subject based on the ideXlab platform.
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second order classical perturbation theory for the Sticking Probability of heavy atoms scattered on surfaces
Journal of Chemical Physics, 2015Co-Authors: Tapas Sahoo, Eli PollakAbstract:A second order classical perturbation theory is developed to calculate the Sticking Probability of a particle scattered from an uncorrugated thermal surface. An analytic expression for the temperature dependent energy loss of the particle to the surface is derived by employing a one-dimensional generalized Langevin equation. The surface temperature reduces the energy loss, since the thermal surface transfers energy to the particle. Using a Gaussian energy loss kernel and the multiple collision theory of Fan and Manson [J. Chem. Phys. 130, 064703 (2009)], enables the determination of the fraction of particles trapped on the surface after subsequent momentum reversals of the colliding particle. This then leads to an estimate of the trapping Probability. The theory is tested for the model scattering of Ar on a LiF(100) surface. Comparison with numerical simulations shows excellent agreement of the analytical theory with simulations, provided that the energy loss is determined by the second order perturbation theory.
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classical stochastic theory for the Sticking Probability of atoms scattered on surfaces
Journal of Physical Chemistry A, 2011Co-Authors: Eli PollakAbstract:A stochastic theory is formulated for the Sticking Probability of a projectile scattered from a surface. The theory is then explored by applying it to a generalized Langevin equation model of the scattering dynamics. The theory succeeds in describing the known features of trapping on surfaces. At low energies Sticking will occur only if there is an attractive interaction between the projectile and the surface. The Probability of Sticking at low energies is greater the lower the temperature and the deeper the attractive well of the particle as it approaches the surface. The Sticking Probability in the absence of horizontal friction tends to be lower as the stiffness of the surface increases. However, in the presence of horizontal friction, increased stiffness may lead to an increase in the Sticking coefficient. A cos(2)(θ(i)) scaling is found only in the absence of corrugation and horizontal friction. The theory is then applied successfully to describe experimentally measured Sticking probabilities for the scattering of Xe on a Pt(111) surface.
D Menzel - One of the best experts on this subject based on the ideXlab platform.
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the coverage dependence of the Sticking Probability of ar on ru 001
Journal of Chemical Physics, 1991Co-Authors: Martin Headgordon, John C Tully, H Schlichting, D MenzelAbstract:The coverage dependence of the Sticking Probability of argon on a cold Ru(001) surface is studied experimentally by thermal‐desorption spectrometry, and simulated by classical molecular dynamics with an empirical pairwise‐additive potential‐energy function. Experimentally, a dramatic linear increase in Sticking as a function of Ar coverage is observed between 0 and 0.7 monolayer for a 300 K thermal beam of Ar incident normal to the surface; at higher coverages the Sticking Probability gradually saturates to approach unity beyond 2 monolayers. The linear regime is reproduced with near‐quantitative accuracy by the simulations, with a simple perfect islanding model. The origin of the enhanced Sticking lies primarily in efficient energy transfer to the adsorbate, due to perfect mass matching and the deformability of the overlayer. In the simulations at incident energies above 50 kJ mol−1 the Sticking on the monolayer diminishes to almost zero, and collision‐induced desorption is observed. Additionally, severa...
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The coverage dependence of the Sticking Probability of Ar on Ru(001)
The Journal of Chemical Physics, 1991Co-Authors: Martin Head-gordon, John C Tully, H Schlichting, D MenzelAbstract:The coverage dependence of the Sticking Probability of argon on a cold Ru(001) surface is studied experimentally by thermal‐desorption spectrometry, and simulated by classical molecular dynamics with an empirical pairwise‐additive potential‐energy function. Experimentally, a dramatic linear increase in Sticking as a function of Ar coverage is observed between 0 and 0.7 monolayer for a 300 K thermal beam of Ar incident normal to the surface; at higher coverages the Sticking Probability gradually saturates to approach unity beyond 2 monolayers. The linear regime is reproduced with near‐quantitative accuracy by the simulations, with a simple perfect islanding model. The origin of the enhanced Sticking lies primarily in efficient energy transfer to the adsorbate, due to perfect mass matching and the deformability of the overlayer. In the simulations at incident energies above 50 kJ mol−1 the Sticking on the monolayer diminishes to almost zero, and collision‐induced desorption is observed. Additionally, several interesting dynamical effects which have experimental relevance emerge from the simulations, such as prolonged impacts and Sticking mediated by attractive interactions at the edge of adsorbate islands.
Hidetoshi Saitoh - One of the best experts on this subject based on the ideXlab platform.
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Measurements of density and Sticking Probability of CN(X2Σ+) radicals by laser-induced fluorescence spectroscopy
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2006Co-Authors: Haruhiko Ito, Kouichi Oda, Yoshinori Kawamura, Hidetoshi SaitohAbstract:CN(X2Σ+) radicals were produced by the decomposition of BrCN with the microwave discharge flow of Ar under the conditions of Ar pressure in the range of 0.40–0.70 Torr. The laser-induced fluorescence (LIF) spectra of the CN(A2Πi–X2Σ+), 4–0, 5–1, and 7–2 bands were observed, and their intensities were calibrated against Rayleigh-scattering intensity by Ar atoms, from which the CN(X2Σ+) radical density (nCN(X)) was determined as (0.67 ± 0.25) × 1018 to (4.42 ± 0.83) × 1018 m−3. Hydrogenated amorphous carbon nitride (a-CNx:H) films were formed by depositing the CN(X2Σ+) radicals on Si substrates in the same reaction system as LIF. The Sticking Probability (s) of the CN(X2Σ+) radicals onto the a-CNx:H films was determined by using nCN(X), the flow speed, and the weight (w) of a-CNx:H. The s value was determined as (6.4 ± 6.4) × 10−2 to (2.5 ± 1.2) × 10−2, where the errors are predominantly determined by those in nCN(X) and w. The procedure described in the present study will provide a methodology to determine the Sticking Probability of the precursor radicals of the film formation based on the gas-phase LIF spectroscopy.
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Sticking Probability of the cn x2σ radicals onto the hydrogenated amorphous carbon nitride films
Thin Solid Films, 2006Co-Authors: Haruhiko Ito, Kouichi Oda, Hidetoshi SaitohAbstract:The Sticking Probability (s) of the CN(X 2 Σ + ) radicals onto the hydrogenated amorphous carbon nitride (a-CN x :H) films was determined by measuring the density of CN(X 2 Σ + ) in the gas phase, the flow speed, and the weight of a-CN x :H. The CN(X 2 Σ + ) radicals were produced by the dissociative excitation reaction of BrCN with the microwave discharge flow of Ar, and were observed by the laser induced fluorescence (LIF) spectroscopy of the CN(A 2 Π t -X 2 Σ + ), 4-0, 5-1, and 7-2 bands. The LIF intensity was calibrated against Rayleigh scattering intensity by Ar atoms, from which the density of CN(X 2 Σ + ) was determined as 1.0 x 10 18 -4.9 × 10 18 m -3 depending on the pressure of Ar (P Ar ) as 0.4-0.7 Torr. The s value was in the range of 0.032-0.019 which was also dependent on P Ar . According to the IR observation of the a-CN x :H films, the P Ar -dependence of s was found to originate in the reactivity of the CN radicals on the film surface.
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absolute density and Sticking Probability of the cn x2σ radicals produced by the dissociative excitation reaction of brcn with the microwave discharge flow of ar
Japanese Journal of Applied Physics, 2003Co-Authors: Haruhiko Ito, Shinya Ichimura, Keiichi Namiki, Hidetoshi SaitohAbstract:The 4-0, 5-1, and 7-2 bands of the A2Πi–X2Σ+ transition of the CN radical produced by the dissociative excitation reaction of BrCN with the microwave discharge flow of Ar were observed by laser induced fluorescence (LIF) spectroscopy. The intensity of the LIF spectrum of the individual transition was evaluated by a spectral simulation analysis, and converted to the absolute value by calibrating against Rayleigh scattering by Ar atoms. The effective lifetime of the A2Πi state was measured to be 2.2(5) µs. The absolute number density of the CN(X2Σ+) radicals in the observation region of LIF was evaluated to be 1.5(3)×1020 m-3. Based on this value, the pumping speed, and the amount of a-CNx:H film deposited, the Sticking Probability of the CN radicals onto the a-CNx:H films was estimated to be 0.01.
