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Tsuneo Urisu - One of the best experts on this subject based on the ideXlab platform.
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New infrared reflection absorption Spectroscopy (IRRAS) system for observation of solid–solution interface biomaterials
Chemical Physics Letters, 2008Co-Authors: Abu Sayed, Hidetaka Uno, Kensuke Harada, Keiichi Tanaka, Yong-hoon Kim, Yuichiro Nakaoki, Koji Okumura, Ryugo Tero, Tsuneo UrisuAbstract:Abstract We have constructed a new system of narrow gap infrared reflection absorption Spectroscopy (NG-IRRAS) for solid–solution interface biomaterials. A sample solution is confined in a narrow space between the CaF 2 prism and the substrate surface. The sample holder is specially designed to keep the narrow space constant during the measurement process. Absorption spectra of the solution phase immunoglobulin G (IgG) and the solid–solution interface IgG covalently bonded to the carboxyl-terminated self-assembled monolayer on the gold surface have been clearly observed with good reproducibility. Noticeable molecular conformation change induced by adsorption was not observed.
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Initial Stage of Hydrogen Etching of Si Surfaces Investigated by Infrared Reflection Absorption Spectroscopy.
Japanese Journal of Applied Physics, 2000Co-Authors: Hideyuki Noda, Tsuneo Urisu, Yoshihiro Kobayashi, Toshio OginoAbstract:The initial stage of etching reactions (breaking the Si–Si back bonds) of Si(100) and Si(111) surfaces exposed to hydrogen at room temperature was investigated by buried metal layer-infrared reflection absorption Spectroscopy. The peaks of SiH2 scissors and SiH3 deformation modes (
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Synchrotron radiation process and in-situ observation technique: infrared reflection absorption Spectroscopy
Emerging Lithographic Technologies II, 1998Co-Authors: Tsuneo UrisuAbstract:Synchrotron radiation (SR) stimulated etching shows unique material selectivities. SR decomposition of silicon hydrides on Si(100) surface measured by infrared reflection absorption Spectroscopy also shows unique reaction selectivities; SiH 2 and SiH 3 are decomposed but SiH is not. These material selectivities are qualitatively explained by the quenching of the excited electronic states. The material selectivity, reaction selectivity by the excitation energy tuning to the specific core electron excitations, and extremely high spatial resolutions owing to the short wavelength nature, SR stimulated etching is a potentially powerful technique for the nanometric processes.
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Measurement of adsorbed F atoms on a HF treated Si surface using infrared reflection absorption Spectroscopy
Applied Physics Letters, 1995Co-Authors: Yoshiyasu Yamada, Tsuneo Urisu, Tadashi Hattori, Hisayoshi OhshimaAbstract:Si(111) surface treated with HF solution was studied using Fourier transform infrared reflection absorption Spectroscopy for the observation of Si–Fx bond absorption and x‐ray photoelectron Spectroscopy for the identification of the adsorbates on the Si surface. Two absorption peaks were observed in the range of 905–925 cm−1, and they were assigned to Si–F2 symmetric stretching mode at 918 cm−1 and Si–H2 bending mode at 910 cm−1. The absorption peak of Si–F2 distinctly decreased with de‐ionized water rinse, though the Si–H2 peak hardly changed. The absorption peak of Si–F was not observed in all spectra. This result indicates that F atoms selectively adsorbed at a step region rather than on a terrace region on Si(111) surface after HF treatment.
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Buried metal layer enhanced infrared reflection absorption Spectroscopy for photoreactions induced by synchrotron radiation on SiO2 surfaces
Applied Surface Science, 1994Co-Authors: Y. Zhang, Tadashi Hattori, S. Sato, H. Ohshima, Tsuneo UrisuAbstract:Abstract In order to monitor the photoreaction upon VUV synchrotron radiation processing of semiconductor materials, combined with a specially prepared substrate that had a buried metal layer, infrared reflection absorption Spectroscopy (IRAS) was developed to carry out in situ detection of chemical changes on the Si or SiO2 surface. Infrared spectra of iron pentacarbonyl and trimethylaluminum adsorbates in submonolayer quantities were obtained. Both molecules were found physisorbing on the SiO2 surface at T 150 nm) or VUV (λ > 1 nm) synchrotron radiation, the adsorbed dimer Al2(CH3)6 was decomposed, leaving methyl-bearing photofragments on the surface. Increasing the surface temperature to above 180 K showed that the photoproducts were still found on the surface, whereas the undecomposed dimer precursors desorbed.
Bernard Desbat - One of the best experts on this subject based on the ideXlab platform.
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Increasing detectivity of polarization modulation infrared Reflection-Absorption Spectroscopy for the study of ultrathin films deposited on various substrates.
Applied Spectroscopy, 2003Co-Authors: J. Saccani, Bernard Desbat, Thierry Buffeteau, D. BlaudezAbstract:In this paper, we present a simple way to increase the sensitivity of polarization modulation infrared reflection–absorption Spectroscopy (PM-IRRAS) for the study of ultrathin films deposited on dielectric and semiconductor substrates. The enhancement of the absorption band intensity is obtained by reducing the signal arising from the substrate. This is achieved by adding a polarizer after the sample in order to balance the polarized reflectivities of the sample. As a consequence, the contribution of the film to the PM-IRRAS signal is increased relative to that of the substrate. An enhancement factor of about 10 has been obtained for ultrathin organic films deposited on glass and spread at the air–water interface. This method has also allowed the study of the very thin native oxide layer present on silicon without the need for the reference spectrum of bare silicon.
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Effect of Cations on the Dissociation of Arachidic Acid Monolayers on Water Studied by Polarization-Modulated Infrared Reflection−Absorption Spectroscopy
Langmuir, 2001Co-Authors: E. Le Calvez, D. Blaudez, And T Buffeteau, Bernard DesbatAbstract:We report on the variation of the dissociation of a Langmuir monolayer of arachidic acid at the air/water interface as a function of the subphase pH and for several cations (Cd2+, Ca2+, Mg2+, and Na+) with the help of the polarization-modulated infrared reflection−absorption Spectroscopy (PM-IRRAS) method. The infrared spectra give access to the relative concentration of acid and salt molecules and allow us to determine the influence of the subphase pH on the acid dissociation reaction for each cation. It is shown that Na+ obeys the purely electrostatic Gouy−Chapman theory quite well, whereas the behavior of Mg2+, and even more so that of Ca2+ and Cd2+, requires the introduction of some complexation constant to be understood.
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effect of cations on the dissociation of arachidic acid monolayers on water studied by polarization modulated infrared reflection absorption Spectroscopy
Langmuir, 2001Co-Authors: Le E Calvez, D. Blaudez, And T Buffeteau, Bernard DesbatAbstract:We report on the variation of the dissociation of a Langmuir monolayer of arachidic acid at the air/water interface as a function of the subphase pH and for several cations (Cd2+, Ca2+, Mg2+, and Na+) with the help of the polarization-modulated infrared reflection−absorption Spectroscopy (PM-IRRAS) method. The infrared spectra give access to the relative concentration of acid and salt molecules and allow us to determine the influence of the subphase pH on the acid dissociation reaction for each cation. It is shown that Na+ obeys the purely electrostatic Gouy−Chapman theory quite well, whereas the behavior of Mg2+, and even more so that of Ca2+ and Cd2+, requires the introduction of some complexation constant to be understood.
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Characterization of the melting–crystallization transition of alcohol monolayers at the air/water interface by polarization modulation infrared reflection absorption Spectroscopy
Chemical Physics Letters, 1998Co-Authors: Coralie Alonso, D. Blaudez, Bernard Desbat, Franck Artzner, Bruno Berge, Anne RenaultAbstract:Abstract Monolayers of 1- and 2-alcohols of varying lengths have been studied at the water surface using polarization modulation infrared reflection absorption Spectroscopy. At the melting of the monolayer, we observe for all compounds a sudden increase of the conformational defects. In the liquid phase the alkyl chains contain gauche defects whereas they are all-trans in the solid phase. In addition, the chains are vertical or tilted by a few degrees with respect to the normal to the surface and the anchorage of molecules at the water surface is ensured by hydrogen bonding.
D. Blaudez - One of the best experts on this subject based on the ideXlab platform.
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Increasing detectivity of polarization modulation infrared Reflection-Absorption Spectroscopy for the study of ultrathin films deposited on various substrates.
Applied Spectroscopy, 2003Co-Authors: J. Saccani, Bernard Desbat, Thierry Buffeteau, D. BlaudezAbstract:In this paper, we present a simple way to increase the sensitivity of polarization modulation infrared reflection–absorption Spectroscopy (PM-IRRAS) for the study of ultrathin films deposited on dielectric and semiconductor substrates. The enhancement of the absorption band intensity is obtained by reducing the signal arising from the substrate. This is achieved by adding a polarizer after the sample in order to balance the polarized reflectivities of the sample. As a consequence, the contribution of the film to the PM-IRRAS signal is increased relative to that of the substrate. An enhancement factor of about 10 has been obtained for ultrathin organic films deposited on glass and spread at the air–water interface. This method has also allowed the study of the very thin native oxide layer present on silicon without the need for the reference spectrum of bare silicon.
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Effect of Cations on the Dissociation of Arachidic Acid Monolayers on Water Studied by Polarization-Modulated Infrared Reflection−Absorption Spectroscopy
Langmuir, 2001Co-Authors: E. Le Calvez, D. Blaudez, And T Buffeteau, Bernard DesbatAbstract:We report on the variation of the dissociation of a Langmuir monolayer of arachidic acid at the air/water interface as a function of the subphase pH and for several cations (Cd2+, Ca2+, Mg2+, and Na+) with the help of the polarization-modulated infrared reflection−absorption Spectroscopy (PM-IRRAS) method. The infrared spectra give access to the relative concentration of acid and salt molecules and allow us to determine the influence of the subphase pH on the acid dissociation reaction for each cation. It is shown that Na+ obeys the purely electrostatic Gouy−Chapman theory quite well, whereas the behavior of Mg2+, and even more so that of Ca2+ and Cd2+, requires the introduction of some complexation constant to be understood.
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effect of cations on the dissociation of arachidic acid monolayers on water studied by polarization modulated infrared reflection absorption Spectroscopy
Langmuir, 2001Co-Authors: Le E Calvez, D. Blaudez, And T Buffeteau, Bernard DesbatAbstract:We report on the variation of the dissociation of a Langmuir monolayer of arachidic acid at the air/water interface as a function of the subphase pH and for several cations (Cd2+, Ca2+, Mg2+, and Na+) with the help of the polarization-modulated infrared reflection−absorption Spectroscopy (PM-IRRAS) method. The infrared spectra give access to the relative concentration of acid and salt molecules and allow us to determine the influence of the subphase pH on the acid dissociation reaction for each cation. It is shown that Na+ obeys the purely electrostatic Gouy−Chapman theory quite well, whereas the behavior of Mg2+, and even more so that of Ca2+ and Cd2+, requires the introduction of some complexation constant to be understood.
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Characterization of the melting–crystallization transition of alcohol monolayers at the air/water interface by polarization modulation infrared reflection absorption Spectroscopy
Chemical Physics Letters, 1998Co-Authors: Coralie Alonso, D. Blaudez, Bernard Desbat, Franck Artzner, Bruno Berge, Anne RenaultAbstract:Abstract Monolayers of 1- and 2-alcohols of varying lengths have been studied at the water surface using polarization modulation infrared reflection absorption Spectroscopy. At the melting of the monolayer, we observe for all compounds a sudden increase of the conformational defects. In the liquid phase the alkyl chains contain gauche defects whereas they are all-trans in the solid phase. In addition, the chains are vertical or tilted by a few degrees with respect to the normal to the surface and the anchorage of molecules at the water surface is ensured by hydrogen bonding.
D. W. Goodman - One of the best experts on this subject based on the ideXlab platform.
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Infrared Reflection Absorption Spectroscopy Study of CO Adsorption and Reaction on Oxidized Pd(100)
The Journal of Physical Chemistry C, 2008Co-Authors: Feng Gao, M. Lundwall, D. W. GoodmanAbstract:The adsorption, desorption, and reaction of CO on the (√5×√5)R27° surface oxide on Pd(100) grown by two methods was investigated with infrared reflection absorption Spectroscopy. CO multilayer desorbs at ∼40 K, whereas monolayer desorption is complete at ∼210 K. The surface oxide formed at 575 K with a 600 Langmuir (L) exposure of O2 exhibits a stronger interaction with CO compared with a surface oxide formed at 575 K with a 4500 L O2 exposure, presumably due to defects in the former. The surface oxide formed with a lower exposure of O2 exhibits enhanced reactivity with CO at 400 K. Below 60 K, O2 blocks CO adsorption on the monolayer oxide.
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Interaction of NO with the MgO(100) surface studied by infrared reflection absorption Spectroscopy
Langmuir, 2002Co-Authors: C. M. Kim, Byoung Koun Min, A. K. Santra, D. W. GoodmanAbstract:Infrared reflection absorption Spectroscopy (IRAS) at low temperatures (ca. 40 K) has been used to study the interaction of NO with highly ordered MgO(100) thin films. Dimer formation has been observed in the multilayer regime at (
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Infrared Reflection-Absorption Spectroscopy and STM Studies of Model Silica-Supported Copper Catalysts
Science, 1992Co-Authors: S. M. Vesecky, D. W. GoodmanAbstract:The structure of model silica-supported copper catalysts has been investigated with scanning tunneling microscopy (STM) and infrared Reflection-Absorption Spectroscopy (IRAS). The IRAS studies of CO on the model silica-supported copper catalysts indicate that there are several types of copper clusters with surface structures similar to (111), (110), and other high-index planes of single-crystal copper. The STM studies show several types of copper clusters on silica and reveal images of metal clusters on an amorphous oxide support with atomic resolution.
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Studies of bimetallic surfaces using infrared reflection absorption Spectroscopy
Journal of Vacuum Science & Technology A: Vacuum Surfaces and Films, 1992Co-Authors: W. Kevin Kuhn, D. W. GoodmanAbstract:Well‐defined bimetallic surfaces have been studied using carbon monoxide adsorption in conjunction with infrared reflection–absorption Spectroscopy. The vibrational frequency of CO on low Cu coverages [∼0.1 monolayer (ML)] on Rh(100) and Mo(110) is blue‐shifted relative to its gas phase stretching frequency of 2143 cm−1. This blue shift is explained as arising from CO adsorbed on well‐dispersed Cu adatoms which are slightly positively charged due to polarization arising from the CO–Cu interaction. As the sample temperature is increased to 150–200 K, CO becomes mobile on these surfaces as evidenced by the migration of CO from submonolayer Pd overlayers to a W(110) substrate. Three‐dimensional Cu clusters, well‐ordered pseudomorphic two‐dimensional Cu islands, and single Cu atoms are distinctively characterized by their CO infrared (IR) peaks. In addition, it is found that IR spectra of adsorbed CO show a remarkable sensitivity to surface structural phase transitions. Both order–order and disorder–order tra...
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Adsorption of CO on Rh(100) studied by infrared reflection–absorption Spectroscopy
The Journal of Chemical Physics, 1990Co-Authors: L.‐w. H. Leung, D. W. GoodmanAbstract:The interaction of CO with a Rh(100) surface at 90 and 300 K has been investigated with infrared reflection–absorption Spectroscopy (IRAS). Absorption bands due to the C–O stretch are found in both the linear and bridging regions at all coverages for both adsorption temperatures. For adsorption at 300 K, an ordered CO layer is formed at ∼0.4 monolayers (ML) as evidenced by a sharp, highly symmetrical, linear‐CO band. At θCO>0.45 ML, the reduction in intermolecular separation and increasing intermolecular repulsive forces in the CO adlayer are evidenced by the increased broadness of both the linear‐ and the bridged‐CO bands. CO adsorption at 90 K yields a nonuniform adlayer dominated by island formation at θCO
James E. Lawler - One of the best experts on this subject based on the ideXlab platform.
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Ultraviolet reflection–absorption Spectroscopy of C6H6 physisorbed on gold
Chemical Physics Letters, 2000Co-Authors: J. R. Peck, X. L. Peng, L. W. Anderson, James E. LawlerAbstract:Abstract Reflection–absorption Spectroscopy in the ultraviolet (UV) of C6H6 molecules physisorbed on a gold surface has been observed in a single-pass experiment for the electronic transition 1 A 1g → 1 B 2u near 250 nm. The linewidths of transitions in this electronic band are 160 cm−1. This technique permits the detection of a very low density of molecules physisorbed on a surface.
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Ultraviolet reflection–absorption Spectroscopy of benzene on metal surfaces
Journal of Applied Physics, 2000Co-Authors: X. L. Peng, J. R. Peck, L. W. Anderson, C. J. Goebel, James E. LawlerAbstract:This article reports on ultraviolet reflection–absorption Spectroscopy of C6H6 molecules physisorbed on Ag, Cu, and Au surfaces. The electronic 1A1g→1B2u transition of C6H6 at wavelengths near 250 nm is observed. We model the system and obtain center frequencies, linewidths, and estimates of the oscillator strengths for the various vibronic absorptions.