The Experts below are selected from a list of 19914 Experts worldwide ranked by ideXlab platform
James N Oshea - One of the best experts on this subject based on the ideXlab platform.
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charge transfer dynamics of model charge transfer centers of a multicenter water splitting dye complex on rutile tio2 110
Journal of Chemical Physics, 2011Co-Authors: Matthew Weston, Andrew J Britton, James N OsheaAbstract:Charge transfer dynamics between an Adsorbed Molecule and a rutile TiO2(110) surface have been investigated in three organometallic dyes related to multicenter water splitting dye complexes: Ru 535 (cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)-ruthenium(II)), Ru 455 (cis-bis(2,2′-bipyridyl)-(2,2′-bipyridyl-4,4′-dicarboxylic acid)-ruthenium(II)), and Ru 470 (tris(2,2′-bipyridyl-4,4′-dicarboxylic acid)-ruthenium(II)). The adsorption of the dye Molecules on the rutile TiO2(110) surface has been studied using core-level and valence photoemission. Dye Molecules were deposited in situ using ultrahigh vacuum electrospray deposition. Core-level photoemission spectra reveal that each complex bonds to the surface via deprotonation of two carboxylic groups. All three dye complexes show evidence of ultrafast charge transfer to the TiO2 substrate using the core-hole clock implementation of resonant photoemission spectroscopy.
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charge transfer between the au 111 surface and Adsorbed c 60 resonant photoemission and new core hole decay channels
Journal of Chemical Physics, 2010Co-Authors: Andrew J Britton, James N Oshea, Anna Rienzo, Karina SchulteAbstract:The interaction of C60 with the Au(111) surface has been investigated using synchrotron radiation-based electron spectroscopy. Resonant photoelectron spectroscopy and autoionization spectroscopy have been used to probe the coupling between the Molecule and the substrate. Three distinct high energy spectator Auger features were observed that are only evident for a monolayer of C60 chemisorbed to the Au(111) surface and not a multilayer or the clean surface itself. Combined with C 1s x-ray absorption and valence band spectra, the data suggest a decay process not previously reported for this system. This is a spectator decay channel involving electrons transferred from the gold substrate to the Adsorbed Molecule, either in the ground state or during the timescale of the core-hole lifetime. Both possibilities are considered in the interpretation of the results, which support, on balance, a ground state charge transfer.
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adsorption and charge transfer dynamics of bi isonicotinic acid on au 111
Journal of Chemical Physics, 2007Co-Authors: Ben J Taylor, James N Oshea, Louise C Mayor, Janine C Swarbrick, Cristina Isvoranu, Joachim SchnadtAbstract:The interaction of bi-isonicotinic acid (4,4′-dicarboxy-2,2′-bipyridine) with the Au(111) surface has been investigated using electron spectroscopic techniques. Near edge x-ray absorption fine structure (NEXAFS) spectra show that monolayers of the Molecule lie flat to the surface and also reveal that the monolayer is sensitive to the preparation conditions employed. Core level x-ray photoelectron spectroscopy (XPS) shows that the Adsorbed Molecule does not undergo deprotonation upon adsorption. The “core-hole clock” implementation of resonant photoemission has been used to probe the coupling between Molecule and substrate. This technique has revealed the possibility of ultrafast backtransfer from the substrate into the Molecule upon resonant excitation of a N 1s core level electron. This is supported by a NEXAFS and XPS investigation of energy level alignments in the system.
N M Harrison - One of the best experts on this subject based on the ideXlab platform.
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an efficient method for computing the binding energy of an Adsorbed Molecule within a periodic approach the application to vinyl fluoride at rutile tio2 110 surface
Computational Materials Science, 2011Co-Authors: Jessica Scaranto, Giuseppe Mallia, N M HarrisonAbstract:Abstract A model for investigating surface adsorption in the limit of low coverage within a periodic supercell formalism is described. The model facilitates the analysis of the contributions to the adsorption energy in terms of interaction, distortion and binding constants defined between nearest and next-nearest Adsorbed Molecules; both direct and surface-mediated effects are considered. As an example the adsorption of vinyl fluoride at the rutile TiO2(1 1 0) surface is studied.
Jacek Lipkowski - One of the best experts on this subject based on the ideXlab platform.
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measurements of surface concentration and charge number per Adsorbed Molecule for a thiolipid monolayer tethered to the au 111 surface by a long hydrophilic chain
Journal of Electroanalytical Chemistry, 2017Co-Authors: Ryan Seenath, Jay J Leitch, Robert J Faragher, Adrian L Schwan, Jacek LipkowskiAbstract:Abstract The charge number per Adsorbed Molecule and surface concentration of 2,3-di- O -phytanyl- sn -glycero-1-octaethyleneglycol-D,L-α-lipoic acid ester (DPOL) at a Au(111) electrode surface was investigated by chronocoulometry using two different film deposition methods. First, a known amount of the thiolipid was transferred from the air-water interface of a Langmuir trough onto the gold electrode surface via a Langmuir-Blodgett (LB) deposition. The charge density measurements for this monolayer system were used to determine the charge number per Adsorbed DPOL Molecule (electrosorption valency). The observed electrosorption valency values of the Adsorbed DPOL film were much lower than the expected number of transferred electrons for a simple reductive desorption process. In the second deposition method, charge densities were measured for the electrode covered by a self-assembled DPOL monolayer. The electrosorption valency values determined from the LB DPOL film were used to calculate the packing density of the DPOL Molecules within the self-assembled monolayer. The surface concentration of the Molecules within the thiol monolayer with octaethylene glycol chains gave similar results to a related thiolipid with tetraethylene glycol chains (DPTL). This new finding indicates that both of these Molecules (DPTL and DPOL) assume a brush conformation in densely packed self-assembled monolayers.
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measurement of the charge number per Adsorbed Molecule and packing densities of self assembled long chain monolayers of thiols
Langmuir, 2007Co-Authors: Thamara Laredo, Jay J Leitch, Maohui Chen, Ian J Burgess, John Dutcher, Jacek LipkowskiAbstract:We have applied a recently developed method (Langmuir 2006, 22, 5509-5519) to determine charge numbers per Adsorbed Molecule and packing densities in self-assembled monolayers (SAMs) of octadecanethiol (C18SH), a representative long-chain thiol. Our method yields values of area per Molecule that are physically reasonable, in contrast to the popular reductive desorption method, which gives molecular areas that are smaller than those determined by the van der Waals radii. In a nonadsorbing electrolyte, we were able to model the dependence of the charge number per Adsorbed Molecule on the electrode potential, taking into account that the desorption process is a substitution reaction between the solvent and the adsorbate. We have also shown that the charge number per Adsorbed thiol is affected by the specific adsorption of the anion of the electrolyte. In the latter case, the thiol competes for adsorption sites at the surface not only with water but also with the anion of the electrolyte, and this competition has an effect on the measured charge number.
Maki Kawai - One of the best experts on this subject based on the ideXlab platform.
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dissociation pathways of a single dimethyl disulfide on cu 111 reaction induced by simultaneous excitation of two vibrational modes
Journal of Chemical Physics, 2014Co-Authors: Kenta Motobayashi, Ryuichi Arafune, Michiaki Ohara, H Ueba, Maki KawaiAbstract:We present a novel reaction mechanism for a single Adsorbed Molecule that proceeds via simultaneous excitation of two different vibrational modes excited by inelastic tunneling electrons from a scanning tunneling microscope. Specifically, we analyze the dissociation of a single dimethyl disulfide (DMDS, (CH3S)2) Molecule on Cu(111) by using a versatile theoretical method, which permits us to simulate reaction rates as a function of sample bias voltage. The reaction is induced by the excitation of C-H stretch and S-S stretch modes by a two-electron process at low positive bias voltages. However, at increased voltages, the dissociation becomes a single-electron process that excites a combination mode of these stretches, where excitation of the C-H stretch is the energy source and excitation of the S-S stretch mode enhances the anharmonic coupling rate. A much smaller dissociation yield (few orders of magnitude) at negative bias voltages is understood in terms of the projected density of states of a single D...
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dissociation pathways of a single dimethyl disulfide on cu 111 reaction induced by simultaneous excitation of two vibrational modes
Journal of Chemical Physics, 2014Co-Authors: Kenta Motobayashi, Ryuichi Arafune, Michiaki Ohara, H Ueba, Yousoo Kim, Maki KawaiAbstract:We present a novel reaction mechanism for a single Adsorbed Molecule that proceeds via simultaneous excitation of two different vibrational modes excited by inelastic tunneling electrons from a scanning tunneling microscope. Specifically, we analyze the dissociation of a single dimethyl disulfide (DMDS, (CH3S)2) Molecule on Cu(111) by using a versatile theoretical method, which permits us to simulate reaction rates as a function of sample bias voltage. The reaction is induced by the excitation of C-H stretch and S-S stretch modes by a two-electron process at low positive bias voltages. However, at increased voltages, the dissociation becomes a single-electron process that excites a combination mode of these stretches, where excitation of the C-H stretch is the energy source and excitation of the S-S stretch mode enhances the anharmonic coupling rate. A much smaller dissociation yield (few orders of magnitude) at negative bias voltages is understood in terms of the projected density of states of a single DMDS on Cu(111), which reflects resonant excitation through the molecular orbitals.
Andrew J Britton - One of the best experts on this subject based on the ideXlab platform.
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charge transfer dynamics of model charge transfer centers of a multicenter water splitting dye complex on rutile tio2 110
Journal of Chemical Physics, 2011Co-Authors: Matthew Weston, Andrew J Britton, James N OsheaAbstract:Charge transfer dynamics between an Adsorbed Molecule and a rutile TiO2(110) surface have been investigated in three organometallic dyes related to multicenter water splitting dye complexes: Ru 535 (cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)-ruthenium(II)), Ru 455 (cis-bis(2,2′-bipyridyl)-(2,2′-bipyridyl-4,4′-dicarboxylic acid)-ruthenium(II)), and Ru 470 (tris(2,2′-bipyridyl-4,4′-dicarboxylic acid)-ruthenium(II)). The adsorption of the dye Molecules on the rutile TiO2(110) surface has been studied using core-level and valence photoemission. Dye Molecules were deposited in situ using ultrahigh vacuum electrospray deposition. Core-level photoemission spectra reveal that each complex bonds to the surface via deprotonation of two carboxylic groups. All three dye complexes show evidence of ultrafast charge transfer to the TiO2 substrate using the core-hole clock implementation of resonant photoemission spectroscopy.
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charge transfer between the au 111 surface and Adsorbed c 60 resonant photoemission and new core hole decay channels
Journal of Chemical Physics, 2010Co-Authors: Andrew J Britton, James N Oshea, Anna Rienzo, Karina SchulteAbstract:The interaction of C60 with the Au(111) surface has been investigated using synchrotron radiation-based electron spectroscopy. Resonant photoelectron spectroscopy and autoionization spectroscopy have been used to probe the coupling between the Molecule and the substrate. Three distinct high energy spectator Auger features were observed that are only evident for a monolayer of C60 chemisorbed to the Au(111) surface and not a multilayer or the clean surface itself. Combined with C 1s x-ray absorption and valence band spectra, the data suggest a decay process not previously reported for this system. This is a spectator decay channel involving electrons transferred from the gold substrate to the Adsorbed Molecule, either in the ground state or during the timescale of the core-hole lifetime. Both possibilities are considered in the interpretation of the results, which support, on balance, a ground state charge transfer.