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Hoshi N, Nakamura M, Kubo R, Suzuki R. Enhanced oxygen reduction reaction on caffeine-modified platinum single-crystal electrodes. Commun Chem 2024; 7:23. [PMID: 38310168 PMCID: PMC10838267 DOI: 10.1038/s42004-024-01113-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 01/23/2024] [Indexed: 02/05/2024] Open
Abstract
Enhancing the activity of the oxygen reduction reaction (ORR) is crucial for fuel cell development, and hydrophobic species are known to increase the ORR activity. This paper reports that caffeine enhanced the specific ORR activity of Pt(111) 11-fold compared to that without caffeine in a 0.1 M HClO4 aqueous solution. Moreover, caffeine increased the ORR activity of Pt(110) 2.5-fold; however, the activity of Pt(100) was unaffected. The infrared (IR) band of PtOH (blocking species of the ORR) decreased for all the surfaces. Caffeine was adsorbed with its molecular plane perpendicular to the Pt(111) and Pt(110) surfaces and tilted relative to the Pt(100) surface. Thus, the effects of caffeine on the ORR activity can be rationalized by a decrease in PtOH coverage and the difference in adsorption geometry of caffeine.
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Affiliation(s)
- Nagahiro Hoshi
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-cho Inage-ku, Chiba, 263-8522, Japan.
| | - Masashi Nakamura
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-cho Inage-ku, Chiba, 263-8522, Japan
| | - Ryuta Kubo
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-cho Inage-ku, Chiba, 263-8522, Japan
| | - Rui Suzuki
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-cho Inage-ku, Chiba, 263-8522, Japan
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2
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Zhang KX, Liu ZP. Electrochemical hydrogen evolution on Pt-based catalysts from a theoretical perspective. J Chem Phys 2023; 158:141002. [PMID: 37061480 DOI: 10.1063/5.0142540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023] Open
Abstract
Hydrogen evolution reaction (HER) by splitting water is a key technology toward a clean energy society, where Pt-based catalysts were long known to have the highest activity under acidic electrochemical conditions but suffer from high cost and poor stability. Here, we overview the current status of Pt-catalyzed HER from a theoretical perspective, focusing on the methodology development of electrochemistry simulation, catalytic mechanism, and catalyst stability. Recent developments in theoretical methods for studying electrochemistry are introduced, elaborating on how they describe solid-liquid interface reactions under electrochemical potentials. The HER mechanism, the reaction kinetics, and the reaction sites on Pt are then summarized, which provides an atomic-level picture of Pt catalyst surface dynamics under reaction conditions. Finally, state-of-the-art experimental solutions to improve catalyst stability are also introduced, which illustrates the significance of fundamental understandings in the new catalyst design.
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Affiliation(s)
- Ke-Xiang Zhang
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Zhi-Pan Liu
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China
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3
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Kubo R, Nakamura M, Hoshi N. Infrared reflection absorption spectroscopy of the adsorbed structures of a protic ionic liquid on the low-index planes of Pt. J Electroanal Chem (Lausanne) 2023. [DOI: 10.1016/j.jelechem.2023.117395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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4
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Zhang J, Tan J, Pei R, Ye S, Luo Y. Ordered Water Layer on the Macroscopically Hydrophobic Fluorinated Polymer Surface and Its Ultrafast Vibrational Dynamics. J Am Chem Soc 2021; 143:13074-13081. [PMID: 34384210 DOI: 10.1021/jacs.1c03581] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydrophobic-like water monolayers have been predicted at the metal and some polar surfaces by theoretical simulations. However, direct experimental evidence for the presence of this water layer at surfaces, particularly at biomolecule and polymer surfaces, is yet to be validated at room temperature. Here we observe experimentally that an ordered molecular water layer is present at the hydrophobic fluorinated polymer such as polytetrafluoroethylene (PTFE) surface by using sum frequency generation vibrational spectroscopy. The macroscopic hydrophobicity of PTFE surface is actually hydrophilic at the molecular level. The macroscopically hydrophobic character of PTFE is indeed resulting from the hydrophobicity of the ordered two-dimension (2D) water layer, in which cyclic water tetramer structure is found. The water layer at humidity of ≤40% has a vibrational relaxation time of 550 ± 60 fs. The vibrational relaxation time in the frequency range of 3200-3400 cm-1 shows remarkable difference from the interfacial water at the air/H2O interface and the lipid/H2O interface. No discernible frequency dependence of the vibrational relaxation time is observed, indicating the homogeneous dynamics of OH groups in the water layer. These insights into the water layer at the macroscopically hydrophobic surface may contribute to a better understanding of the hydrophobic interaction and interfacial water dynamics.
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Affiliation(s)
- Jiahui Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Junjun Tan
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ruoqi Pei
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shuji Ye
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yi Luo
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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Hoshi N, Nakamura M. Enhancement of the Activity for the Oxygen Reduction Reaction on Well-defined Single Crystal Electrodes of Pt by Hydrophobic Species. CHEM LETT 2021. [DOI: 10.1246/cl.200608] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Nagahiro Hoshi
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Masashi Nakamura
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
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6
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Sugimoto T, Matsumoto Y. Orientational ordering in heteroepitaxial water ice on metal surfaces. Phys Chem Chem Phys 2020; 22:16453-16466. [DOI: 10.1039/d0cp01763a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sum frequency generation spectroscopy uncovers the orientational ordering in crystalline ice films of water grown on Pt(111) and Rh(111).
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Affiliation(s)
- Toshiki Sugimoto
- Department of Materials Molecular Science
- Institute for Molecular Science
- Myodaiji
- Okazaki
- Japan
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7
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Hoshi N, Saikawa K, Nakamura M. Structural effects on water molecules on the low index planes of Pt modified with alkyl amines and the correlation with the activity of the oxygen reduction reaction. Electrochem commun 2019. [DOI: 10.1016/j.elecom.2019.106536] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Niu F, Rabe M, Nayak S, Erbe A. Vibrational spectroscopic study of pH dependent solvation at a Ge(100)-water interface during an electrode potential triggered surface termination transition. J Chem Phys 2018; 148:222824. [PMID: 29907053 DOI: 10.1063/1.5018796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The charge-dependent structure of interfacial water at the n-Ge(100)-aqueous perchlorate interface was studied by controlling the electrode potential. Specifically, a joint attenuated total reflection infrared spectroscopy and electrochemical experiment was used in 0.1M NaClO4 at pH ≈ 1-10. The germanium surface transformation to an H-terminated surface followed the thermodynamic Nernstian pH dependence and was observed throughout the entire pH range. A singular value decomposition-based spectra deconvolution technique coupled to a sigmoidal transition model for the potential dependence of the main components in the spectra shows the surface transformation to be a two-stage process. The first stage was observed together with the first appearance of Ge-H stretching modes in the spectra and is attributed to the formation of a mixed surface termination. This transition was reversible. The second stage occurs at potentials ≈0.1-0.3 V negative of the first one, shows a hysteresis in potential, and is attributed to the formation of a surface with maximum Ge-H coverage. During the surface transformation, the surface becomes hydrophobic, and an effective desolvation layer, a "hydrophobic gap," developed with a thickness ≈1-3 Å. The largest thickness was observed near neutral pH. Interfacial water IR spectra show a loss of strongly hydrogen-bound water molecules compared to bulk water after the surface transformation, and the appearance of "free," non-hydrogen bound OH groups, throughout the entire pH range. Near neutral pH at negative electrode potentials, large changes at wavenumbers below 1000 cm-1 were observed. Librational modes of water contribute to the observed changes, indicating large changes in the water structure.
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Affiliation(s)
- Fang Niu
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany
| | - Martin Rabe
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany
| | - Simantini Nayak
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany
| | - Andreas Erbe
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany
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9
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Saikawa K, Nakamura M, Hoshi N. Structural effects on the enhancement of ORR activity on Pt single-crystal electrodes modified with alkylamines. Electrochem commun 2018. [DOI: 10.1016/j.elecom.2017.12.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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10
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Niu F, Schulz R, Castañeda Medina A, Schmid R, Erbe A. Electrode potential dependent desolvation and resolvation of germanium(100) in contact with aqueous perchlorate electrolytes. Phys Chem Chem Phys 2017; 19:13585-13595. [PMID: 28513645 DOI: 10.1039/c6cp08908a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electrode potential dependence of the hydration layer on an n-Ge(100) surface was studied by a combination of in situ and operando electrochemical attenuated total reflection infrared (ATR-IR) spectroscopy and real space density functional theory (DFT) calculations. Constant-potential DFT calculations were coupled to a modified generalised Poisson-Boltzmann ion distribution model and applied within an ab initio molecular dynamics (AIMD) scheme. As a result, potential-dependent vibrational spectra of surface species and surface water were obtained, both experimentally and by simulations. The experimental spectra show increasing absorbance from the Ge-H stretching modes at negative potentials, which is associated with an increased negative difference absorbance of water-related OH modes. When the termination transition of germanium from OH to H termination occurs, the surface switches from hydrophilic to hydrophobic. This transition is fully reversible. During the switching, the interface water molecules are displaced from the surface forming a "hydrophobic gap". The gap thickness was experimentally estimated by a continuum electrodynamic model to be ≈2 Å. The calculations showed a shift in the centre of mass of the interface water by ≈0.9 Å due to the surface transformation. The resulting IR spectra of the interfacial water in contact with the hydrophobic Ge-H show an increased absorbance of free OH groups, and a decreased absorbance of strongly hydrogen bound water. Consequently, the surface transformation to a Ge-H terminated surface leads to a surface which is weakening the H-bond network of the interfacial water in contact.
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Affiliation(s)
- Fang Niu
- Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany.
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12
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den Dunnen A, van der Niet MJTC, Badan C, Koper MTM, Juurlink LBF. Long-range influence of steps on water adsorption on clean and D-covered Pt surfaces. Phys Chem Chem Phys 2015; 17:8530-7. [DOI: 10.1039/c4cp03165b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Water wets the D-covered Pt(111) surface (right), while it clusters at steps of D-covered Pt(533), (755), and (977) (left).
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Affiliation(s)
- Angela den Dunnen
- Leiden Institute of Chemistry
- Leiden University
- 2300 RA Leiden
- The Netherlands
| | | | - Cansin Badan
- Leiden Institute of Chemistry
- Leiden University
- 2300 RA Leiden
- The Netherlands
| | - Marc T. M. Koper
- Leiden Institute of Chemistry
- Leiden University
- 2300 RA Leiden
- The Netherlands
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13
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Sanchéz-Lozano M, Mandado M, Pérez-Juste I, Hermida-Ramón JM. Theoretical vibrational Raman and surface-enhanced Raman scattering spectra of water interacting with silver clusters. Chemphyschem 2014; 15:4067-76. [PMID: 25263101 DOI: 10.1002/cphc.201402454] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Indexed: 11/11/2022]
Abstract
In this study, we analyzed the Raman spectrum of a water molecule adsorbed on a cluster of 20 silver atoms, and the plasmonic electromagnetic effect of the silver surface was also considered to give a theoretical prediction of the surface-enhanced Raman scattering spectrum. The calculations were performed at the density functional theory (DFT) level by using both frozen and unfrozen silver clusters. Two different models were used to consider the plasmonic enhancement; one of them was a modified classical (dipole) model and the other was the coupled perturbed Hartree-Fock method with excitation frequencies obtained from time-dependent DFT calculations and with proper detuning of these frequencies. The importance of small geometrical distortions of the silver surface in the orientation of the adsorbed water was shown. Moreover, it was shown how the symmetry of the transition dipole moment and the symmetry of the vibrational modes influence the Raman intensities of the SERS spectrum.
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Affiliation(s)
- Marta Sanchéz-Lozano
- Departamento de Química Física, Facultade de Química, Universidade de Vigo, Campus Lagoas Marcosende s/n, 36310 Vigo (Spain)
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14
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Motobayashi K, Árnadóttir L, Matsumoto C, Stuve EM, Jónsson H, Kim Y, Kawai M. Adsorption of water dimer on platinum(111): identification of the -OH···Pt hydrogen bond. ACS NANO 2014; 8:11583-11590. [PMID: 25337794 DOI: 10.1021/nn504824z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The fundamental structure of an isolated water dimer on Pt(111) was determined by means of a spectroscopic method using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. Two water molecules on adjacent atop sites form a dimer through a hydrogen bond, and they rotate even at a substrate temperature of 5 K. Action spectroscopy using STM (STM-AS) for water dimer hopping allows us to obtain the vibrational spectrum of a single water dimer on Pt(111). Comparisons between the experiments and theory show that one of the OH groups of the acceptor water molecule points toward the surface to form an -OH···Pt hydrogen bond.
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Affiliation(s)
- Kenta Motobayashi
- Catalysis Research Center, Hokkaido University , Sapporo 001-0021, Japan
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15
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Politano A, Chiarello G. The formation of HOCO in the coadsorption of water and carbon monoxide on Pt3Ni(111). RSC Adv 2014. [DOI: 10.1039/c4ra08066a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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16
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Politano A, Chiarello G. The nature of free O-H stretching in water adsorbed on carbon nanosystems. J Chem Phys 2013; 139:064704. [DOI: 10.1063/1.4817681] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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17
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Tseng HC, Wu JS, Chang RY. Material functions of liquid n-hexadecane under steady shear via nonequilibrium molecular dynamics simulations: temperature, pressure, and density effects. J Chem Phys 2009; 130:084904. [PMID: 19256624 DOI: 10.1063/1.3080768] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Computer experiments of rheology regarding the effects of temperature (T), pressure (P), and density (rho) on steady shear flow material functions, which include viscosity (eta) and first and second normal stress coefficients (psi(1) and psi(2)) depending on shear rate (gamma), have been conducted via nonequilibrium molecular dynamics simulations for liquid n-hexadecane. Straightforwardly, using both characteristic values of a zero-shear-rate viscosity and critical shear rate, eta-gamma flow curves are well normalized to achieve the temperature-, pressure-, and density-invariant master curves, which can be formulary described by the Carreau-Yasuda rheological constitutive equation. Variations in the rate of shear thinning, obviously exhibiting in eta-gamma, psi(1)-gamma, and -psi(2)-gamma relationships, under different T, P, and rho values, are concretely revealed through the power-law model's exponent. More importantly, at low shear rates, the fluid explicitly possesses Newtonian fluidic characteristics according to both manifestations; first and second normal stress differences decay to near zero, while nonequilibrium states are close to equilibrium ones. Significantly, the tendency to vary of the degree of shear thinning in rheology is qualitatively contrary to that of shear dilatancy in thermodynamics. In addition, a convergent transition point is evidently observed in the -psi(2)/psi(1)-gamma curves undergoing dramatic variations, which should be associated with shear dilatancy, as addressed analytically.
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Affiliation(s)
- Huan-Chang Tseng
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan 30010, Republic of China
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18
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Dalakoglou GK, Karatasos K, Lyulin SV, Lyulin AV. Shear-induced effects in hyperbranched-linear polyelectrolyte complexes. J Chem Phys 2008; 129:034901. [DOI: 10.1063/1.2952518] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Tseng HC, Wu JS, Chang RY. Shear thinning and shear dilatancy of liquid n-hexadecane via equilibrium and nonequilibrium molecular dynamics simulations: Temperature, pressure, and density effects. J Chem Phys 2008; 129:014502. [DOI: 10.1063/1.2943314] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Ji X, Yan L, Lu W. New torsion potential expression for molecules without rotational symmetry. J Chem Phys 2008; 128:224101. [DOI: 10.1063/1.2929828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Zimbitas G, Gallagher ME, Darling GR, Hodgson A. Wetting of mixed OH∕H2O layers on Pt(111). J Chem Phys 2008; 128:074701. [DOI: 10.1063/1.2830266] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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22
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Barnette AL, Asay DB, Kim SH. Average molecular orientations in the adsorbed water layers on silicon oxide in ambient conditions. Phys Chem Chem Phys 2008; 10:4981-6. [DOI: 10.1039/b810309g] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Dalakoglou GK, Karatasos K, Lyulin SV, Lyulin AV. Effects of topology and size on statics and dynamics of complexes of hyperbranched polymers with linear polyelectrolytes. J Chem Phys 2007; 127:214903. [DOI: 10.1063/1.2802300] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Qin Y, Fichthorn KA. Molecular dynamics simulation of the forces between colloidal nanoparticles in n-decane solvent. J Chem Phys 2007; 127:144911. [DOI: 10.1063/1.2776259] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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25
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Laso M, Karayiannis NC, Müller M. Min-map bias Monte Carlo for chain molecules: biased Monte Carlo sampling based on bijective minimum-to-minimum mapping. J Chem Phys 2007; 125:164108. [PMID: 17092064 DOI: 10.1063/1.2359442] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A novel Monte Carlo (MC) simulation scheme based on Theodorou's bijective mapping strategy [D. N. Theodorou, J. Chem. Phys. 124, 034109 (2006)] is introduced. This min-map bias Monte Carlo acts in combination with any other proper, bare MC. It carries over the bare MC move from the original configuration space Omega(0), where trial move acceptance may be low, to a different configuration space, Omega(1), where acceptance is higher. The bare MC move is then performed in Omega(1) and the resulting configuration is finally mapped back to Omega(0). Mappings between Omega(0) and Omega(1) entail weighted selection of trial configurations, the bias of which is subsequently removed in the overall acceptance criterion. The new method is applied, in conjunction with continuum configurational bias as bare MC scheme, to the simulation of explicit hydrogen linear alkanes in the canonical ensemble. Min-map bias MC is found to alleviate the pervasive problem of very low acceptance rates encountered when using an explicit molecular description.
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Affiliation(s)
- Manuel Laso
- Institute for Optoelectronics and Microsystems (ISOM), UPM, José Gutiérrez Abascal 2, E-28006 Madrid, Spain.
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26
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Verdaguer A, Sacha GM, Bluhm H, Salmeron M. Molecular structure of water at interfaces: wetting at the nanometer scale. Chem Rev 2007; 106:1478-510. [PMID: 16608188 DOI: 10.1021/cr040376l] [Citation(s) in RCA: 294] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- A Verdaguer
- Materials Sciences Division and Chemical Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
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27
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Ilnytskyi JM, Neher D. Structure and internal dynamics of a side chain liquid crystalline polymer in various phases by molecular dynamics simulations: a step towards coarse graining. J Chem Phys 2007; 126:174905. [PMID: 17492884 DOI: 10.1063/1.2712438] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Side chain liquid crystalline polymer with relatively long spacer was modeled on a semiatomistic level and studied in different liquid crystalline phases with the aid of molecular dynamics simulations. Well equilibrated isotropic, polydomain smectic and monodomain smectic phases were studied for their structural and dynamic properties. Particular emphasis was given to the analysis on a coarse-grained level, where backbones, side chains, and mesogens were considered in terms of their equivalent ellipsoids. The authors found that the liquid crystalline phase had a minor influence on the metrics of these objects but affected essentially their translational and orientational order. In the monodomain smectic phase, mesogens, backbones, and side chains are confined spatially. Their diffusion and shape dynamics are frozen along the mesogen director (the one-dimensional solidification) and the reorientation times increase by one to one-and-half orders of magnitude. In this phase, besides obvious orientational order of mesogens and side chains, a stable detectable order of the backbones was also observed. The backbone director is confined in the plane perpendicular to the mesogen director and constantly changes its orientation within this plane. The backbone diffusion in these planes is of the same range as in the polydomain smectic phase at the same temperature. A detailed analysis of the process of field-induced growth of the smectic phase was performed. The study revealed properties of liquid crystalline polymers that may enable their future fully coarse-grained modeling.
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Affiliation(s)
- Jaroslav M Ilnytskyi
- Institute for Physics, University of Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany.
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28
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Wohlert J, Edholm O. Dynamics in atomistic simulations of phospholipid membranes: Nuclear magnetic resonance relaxation rates and lateral diffusion. J Chem Phys 2006; 125:204703. [PMID: 17144719 DOI: 10.1063/1.2393240] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
It is shown that a long, near microsecond, atomistic simulation can shed some light upon the dynamical processes occurring in a lipid bilayer. The analysis focuses on reorientational dynamics of the chains and lateral diffusion of lipids. It is shown that the reorientational correlation functions exhibits an algebraic decay (rather than exponential) for several orders of magnitude in time. The calculated nuclear magnetic resonance relaxation rates agree with experiments for carbons at the C7 position while there are some differences for C3. Lateral diffusion can be divided into two stages. In a first stage occurring at short times, t<5 ns, the center of mass of the lipid moves due to conformational changes of the chains while the headgroup position remains relatively fixed. In this stage, the center of mass can move up to approximately 0.8 nm. The fitted short-time diffusion coefficient is D(1)=13 x 10(-7) cm(2) s(-1) On a longer time scale, the diffusion coefficient becomes D(2)=0.79 x 10(-7) cm(2) s(-1).
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Affiliation(s)
- Jakob Wohlert
- Theoretical Biological Physics, Department of Theoretical Physics, Royal Institute of Technology, AlbaNova University Center, SE-106 91 Stockholm, Sweden
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Siddick MM, Ackland GJ, Morrison CA. Constrained dynamics and extraction of normal modes fromab initiomolecular dynamics: Application to ammonia. J Chem Phys 2006; 125:64707. [PMID: 16942305 DOI: 10.1063/1.2218848] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a methodology for extracting phonon data from ab initio Born-Oppenheimer molecular dynamics calculations of molecular crystals. Conventional ab initio phonon methods based on perturbations are difficult to apply to lattice modes because the perturbation energy is dominated by intramolecular modes. We use constrained molecular dynamics to eliminate the effect of bond bends and stretches and then show how trajectories can be used to isolate and define in particular, the eigenvalues and eigenvectors of modes irrespective of their symmetry or wave vector. This is done by k-point and frequency filtering and projection onto plane wave states. The method is applied to crystalline ammonia: the constrained molecular dynamics allows a significant speed-up without affecting structural or vibrational modes. All Gamma point lattice modes are isolated: the frequencies are in agreement with previous studies; however, the mode assignments are different.
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Affiliation(s)
- M M Siddick
- School of Physics, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
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30
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Canales M, Sesé G. On the analysis of conformational dynamics in polymers with several rotational isomers. J Chem Phys 2006; 125:054906. [PMID: 16942256 DOI: 10.1063/1.2234775] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ability of different correlation functions to shed some light onto the conformational dynamics of an amorphous polymer has been analyzed. The study has been performed on a polyethylene model polymer, which has been simulated at decreasing temperatures towards its glass transition, via the molecular dynamics technique. Three rotational isomers are allowed by the considered torsional potential. The correlation times associated with the evaluated transition rates have shown to be Arrhenius in nature, with activation energies resulting basically from internal rotation barriers. Overall torsional autocorrelation functions have been calculated. We have observed that they are dominated by slow events. Alternatively, a set of torsional autocorrelation functions associated with every isomeric state has been evaluated. Stretched exponential fits lead to correlation times that display Vogel-Fulcher temperature dependence.
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Affiliation(s)
- Manel Canales
- Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Campus Nord-Mòdul B4, c/ Jordi Girona 1-3, 08034 Barcelona, Spain.
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Wohlert J, den Otter WK, Edholm O, Briels WJ. Free energy of a trans-membrane pore calculated from atomistic molecular dynamics simulations. J Chem Phys 2006; 124:154905. [PMID: 16674263 DOI: 10.1063/1.2171965] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Atomistic molecular dynamics simulations of a lipid bilayer were performed to calculate the free energy of a trans-membrane pore as a function of its radius. The free energy was calculated as a function of a reaction coordinate using a potential of mean constraint force. The pore radius was then calculated from the reaction coordinate using Monte Carlo particle insertions. The main characteristics of the free energy that comes out of the simulations are a quadratic shape for a radius less than about 0.3 nm, a linear shape for larger radii than this, and a rather abrupt change without local minima or maxima between the two regions. In the outer region, a line tension can be calculated, which is consistent with the experimentally measured values. Further, this line tension can be rationalized and understood in terms of the energetic cost for deforming a part of the lipid bilayer into a hydrophilic pore. The region with small radii can be described and understood in terms of statistical mechanics of density fluctuations. In the region of crossover between a quadratic and linear free energy there was some hysteresis associated with filling and evacuation of the pore with water. The metastable prepore state hypothesized to interpret the experiments was not observed in this region.
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Affiliation(s)
- J Wohlert
- Theoretical Biological Physics, Department of Physics, Royal Institute of Technology, AlbaNova University Center, SE-106 91 Stockholm, Sweden.
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Matubayasi N, Liang KK, Nakahara M. Free-energy analysis of solubilization in micelle. J Chem Phys 2006; 124:154908. [PMID: 16674266 DOI: 10.1063/1.2186324] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A statistical-mechanical treatment of the solubilization in micelle is presented in combination with molecular simulation. The micellar solution is viewed as an inhomogeneous and partially finite, mixed solvent system, and the method of energy representation is employed to evaluate the free-energy change for insertion of a solute into the micelle inside with a realistic set of potential functions. Methane, benzene, and ethylbenzene are adopted as model hydrophobic solutes to analyze the solubilization in sodium dodecyl sulfate micelle. It is shown that these solutes are more favorably located within the micelle than in bulk water and that the affinity to the micelle inside is stronger for benzene and ethylbenzene than for methane. The micellar system is then divided into the hydrophobic core, the head-group region in contact with water, and the aqueous region outside the micelle to assess the relative importance of each region in the solubilization. In support of the pseudophase model, the aqueous region is found to be unimportant to determine the extent of solubilization. The contribution from the hydrophobic-core region is shown to be dominant for benzene and ethylbenzene, while an appreciable contribution from the head-group region is observed for methane. The methodology presented is not restricted to the binding of a molecule to micelle, and will be useful in treating the binding to such nanoscale structures as protein and membrane.
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Affiliation(s)
- Nobuyuki Matubayasi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
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Zhao X, Cummings PT. Molecular dynamics study of carbon nanotube oscillators revisited. J Chem Phys 2006; 124:134705. [PMID: 16613466 DOI: 10.1063/1.2185623] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We performed molecular dynamics simulation of double walled carbon nanotube (DWCNT) oscillators under constant energy and constant temperatures with various commensurations and nanotube lengths. We clarify and resolve questions and differences raised by previous simulation results of similar systems. At constant energy, sustained oscillation is available for a wide range of initial temperatures. But low initial temperature is advantageous for DWCNTs to sustain oscillation under constant energy. We observed sustained oscillation at constant energy for both commensurate and incommensurate DWCNTs. On the other hand, under constant temperatures, both high and low temperatures are disadvantageous to sustain DWCNT oscillations. At constant low temperature, neither commensurate nor incommensurate DWCNTs can maintain oscillation. At appropriate constant temperatures, the oscillatory behavior of incommensurate nanotubes is much more sustained than that of commensurate tubes. The oscillatory frequency of DWCNTs depends significantly on the length of tubes. The initial oscillatory frequency is inversely proportional to the DWCNT lengths. The oscillation frequency of DWCNTs is insensitive to the initial temperatures at constant energy, but slightly dependent on the temperature at constant temperatures.
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Affiliation(s)
- Xiongce Zhao
- Nanomaterials Theory Institute, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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Zimbitas G, Haq S, Hodgson A. The structure and crystallization of thin water films on Pt(111). J Chem Phys 2005; 123:174701. [PMID: 16375551 DOI: 10.1063/1.2060691] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
When water is adsorbed on Pt(111) above 135 K several different ice structures crystallize, depending on the thickness of the ice layer. At low coverage water forms extended islands of ice with a (square root(37) x square root(37))R25(o) unit cell, which compresses as the monolayer saturates to form a (square root(39) x square root(39))R16(o) structure. The square root(39) low-energy electron diffraction (LEED) pattern becomes more intense as the second layer grows, remaining bright for films up of 10-15 layers and then fading and disappearing for films more than ca. 40 layers thick. The ice multilayer consists of an ordered square root(39) wetting layer, on which ice grows as a crystalline film which progressively loses its registry to the wetting layer. Ice films more than ca. 50 layers thick develop a hexagonal LEED pattern, the entire film and wetting layer reorienting to form an incommensurate bulk ice. These changes are reflected in the vibrational spectra which show changes in line shape and intensity associated with the different ice structures. Thin amorphous solid water films crystallize to form the same phases observed during growth, implying that these structures are thermodynamically stable and not kinetic phases formed during growth. The change from a square root(39) registry to incommensurate bulk ice at ca. 50 layers is associated with a change in crystallization kinetics from nucleation at the Pt(111) interface in thin films to nucleation of incommensurate bulk ice in amorphous solid water films more than 50 layers thick.
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Affiliation(s)
- G Zimbitas
- Surface Science Research Centre, The University of Liverpool, Oxford Street, Liverpool L69 3BX, United Kingdom
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Yamamoto S, Beniya A, Mukai K, Yamashita Y, Yoshinobu J. Water Adsorption on Rh(111) at 20 K: From Monomer to Bulk Amorphous Ice. J Phys Chem B 2005; 109:5816-23. [PMID: 16851634 DOI: 10.1021/jp044379d] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The adsorption of water (D(2)O) molecules on Rh(111) at 20 K was investigated using infrared reflection absorption spectroscopy (IRAS). At the initial stage of adsorption, water molecules exist as monomers on Rh(111). With increasing water coverage, monomers aggregate into dimers, larger clusters (n = 3-6), and two-dimensional (2D) islands. Further exposure of water molecules leads to the formation of three-dimensional (3D) water islands and finally to a bulk amorphous ice layer. Upon heating, the monomer and dimer species thermally migrate on the surface and aggregate to form larger clusters and 2D islands. Based on the temperature dependence of OD stretching peaks, we succeeded in distinguishing water molecules inside 2D islands from those at the edge of 2D islands. From the comparison with the previous vibrational spectra of water clusters on other metal surfaces, we conclude that the number of water molecules at the edge of 2D islands is comparable with that of water molecules inside 2D islands on the Rh(111) surface at 20 K. This indicates that the surface migration of water molecules on Rh(111) is hindered as compared with the cases on Pt(111) and Ni(111) and thus the size of 2D islands on Rh(111) is relatively small.
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Affiliation(s)
- Susumu Yamamoto
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
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Nakamura M, Ito M. Coadsorption of water dimer and ring-hexamer clusters on M(111) (M=Cu, Ni, Pt) and Ru(001) surfaces at 25K as studied by infrared reflection absorption spectroscopy. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.01.106] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Grecea ML, Backus EHG, Riedmüller B, Eichler A, Kleyn AW, Bonn M. The Interaction of Water with the Pt(533) Surface. J Phys Chem B 2004. [DOI: 10.1021/jp049392c] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mihail L. Grecea
- Leiden Institute of Chemistry, University of Leiden, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands, Institute of Material Science and Center for Computational Materials Science, University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria, FOM Institute for Plasma Physics Rijnhuizen, Euratom-FOM Association, P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands, and FOM Institute for Atomic and Molecular Physics AMOLF, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
| | - Ellen H. G. Backus
- Leiden Institute of Chemistry, University of Leiden, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands, Institute of Material Science and Center for Computational Materials Science, University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria, FOM Institute for Plasma Physics Rijnhuizen, Euratom-FOM Association, P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands, and FOM Institute for Atomic and Molecular Physics AMOLF, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
| | - Bernd Riedmüller
- Leiden Institute of Chemistry, University of Leiden, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands, Institute of Material Science and Center for Computational Materials Science, University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria, FOM Institute for Plasma Physics Rijnhuizen, Euratom-FOM Association, P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands, and FOM Institute for Atomic and Molecular Physics AMOLF, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
| | - Andreas Eichler
- Leiden Institute of Chemistry, University of Leiden, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands, Institute of Material Science and Center for Computational Materials Science, University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria, FOM Institute for Plasma Physics Rijnhuizen, Euratom-FOM Association, P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands, and FOM Institute for Atomic and Molecular Physics AMOLF, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
| | - Aart W. Kleyn
- Leiden Institute of Chemistry, University of Leiden, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands, Institute of Material Science and Center for Computational Materials Science, University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria, FOM Institute for Plasma Physics Rijnhuizen, Euratom-FOM Association, P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands, and FOM Institute for Atomic and Molecular Physics AMOLF, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
| | - Mischa Bonn
- Leiden Institute of Chemistry, University of Leiden, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands, Institute of Material Science and Center for Computational Materials Science, University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria, FOM Institute for Plasma Physics Rijnhuizen, Euratom-FOM Association, P.O. Box 1207, 3430 BE Nieuwegein, The Netherlands, and FOM Institute for Atomic and Molecular Physics AMOLF, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands
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Lilach Y, Buch V, Asscher M. Formation and dynamics of water clusters on Ru(001). J Chem Phys 2003. [DOI: 10.1063/1.1625645] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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40
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Michaelides A, Alavi A, King DA. Different surface chemistries of water on Ru[0001]: from monomer adsorption to partially dissociated bilayers. J Am Chem Soc 2003; 125:2746-55. [PMID: 12603164 DOI: 10.1021/ja028855u] [Citation(s) in RCA: 210] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Density functional theory has been used to perform a comparative theoretical study of the adsorption and dissociation of H(2)O monomers and icelike bilayers on Ru[0001]. H(2)O monomers bind preferentially at atop sites with an adsorption energy of approximately 0.4 eV/H(2)O. The main bonding interaction is through the H(2)O 1b(1) molecular orbital which mixes with Ru d(z)2 states. The lower-lying set of H(2)O molecules in an intact H(2)O bilayer bond in a similar fashion; the high-lying H(2)O molecules, however, do not bond directly with the surface, rather they are held in place through H bonding. The H(2)O adsorption energy in intact bilayers is approximately 0.6 eV/H(2)O and we estimate that H bonding accounts for approximately 70% of this. In agreement with Feibelman (Science 2002, 295, 99) we find that a partially dissociated OH + H(2)O overlayer is energetically favored over pure intact H(2)O bilayers on the surface. The barrier for the dissociation of a chemisorbed H(2)O monomer is 0.8 eV, whereas the barrier to dissociate a H(2)O incorporated in a bilayer is just 0.5 eV.
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Affiliation(s)
- A Michaelides
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K
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41
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Ogasawara H, Brena B, Nordlund D, Nyberg M, Pelmenschikov A, Pettersson LGM, Nilsson A. Structure and bonding of water on Pt(111). PHYSICAL REVIEW LETTERS 2002; 89:276102. [PMID: 12513221 DOI: 10.1103/physrevlett.89.276102] [Citation(s) in RCA: 235] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2002] [Indexed: 05/24/2023]
Abstract
We address the adsorption of water on Pt(111) using x-ray absorption, x-ray emission, and x-ray photoelectron spectroscopy along with calculations in the framework of density functional theory. Using the direct relationship between the electronic structure and adsorbate geometry, we show that in the first layer all the molecules bind directly to the surface and to each other through the in-layer H bonds without dissociation, creating a nearly flat overlayer. The water molecules are adsorbed through alternating metal-oxygen (M-O) and metal-hydrogen (M-HO) bonds.
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Affiliation(s)
- H Ogasawara
- FYSIKUM, Stockholm University, Albanova University Center, S-10691 Stockholm, Sweden
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Mitsui T, Rose MK, Fomin E, Ogletree DF, Salmeron M. Water diffusion and clustering on Pd(111). Science 2002; 297:1850-2. [PMID: 12228712 DOI: 10.1126/science.1075095] [Citation(s) in RCA: 290] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The adsorption, diffusion, and clustering of water molecules on a Pd(111) surface were studied by scanning tunneling microscopy. At 40 kelvin, low-coverage water adsorbs in the form of isolated molecules, which diffuse by hopping to nearest neighbor sites. Upon collision, they form first dimers, then trimers, tetramers, and so on. The mobility of these species increased by several orders of magnitude when dimers, trimers, and tetramers formed, and decreased again when the cluster contained five or more molecules. Cyclic hexamers were found to be particularly stable. They grow with further exposure to form a commensurate hexagonal honeycomb structure relative to the Pd(111) substrate. These observations illustrate the change in relative strength between intermolecular hydrogen bonds and molecule-substrate bonds as a function of water cluster size, the key property that determines the wetting properties of materials.
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Affiliation(s)
- T Mitsui
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA, 94720 USA
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Ohwaki T, Kamegai K, Yamashita K. Electric Field Effects on the Adsorption, Charge Transfer and Vibrational State at Metal Electrodes: A DFT Study on H2O/Pt(111), H2O/Pt(100) and (H2O)2/Pt(111). BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2001. [DOI: 10.1246/bcsj.74.1021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Nakamura M, Ito M. Coadsorption of water monomers with CO on Ru(001) and charge transfer during hydration processes. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)00069-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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45
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Nakamura M, Song MB, Ito M. Hydrogen bonding between a water molecule and electronegative additives (O or Cl-) on a Pt(111) surface. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00257-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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