1
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Han H, Park Y, Kim Y, Ding F, Shin HJ. Controlled dissolution of a single ion from a salt interface. Nat Commun 2024; 15:2401. [PMID: 38493203 PMCID: PMC10944500 DOI: 10.1038/s41467-024-46704-y] [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: 09/16/2023] [Accepted: 03/07/2024] [Indexed: 03/18/2024] Open
Abstract
Interactions between monatomic ions and water molecules are fundamental to understanding the hydration of complex polyatomic ions and ionic process. Among the simplest and well-established ion-related reactions is dissolution of salt in water, which is an endothermic process requiring an increase in entropy. Extensive efforts have been made to date; however, most studies at single-ion level have been limited to theoretical approaches. Here, we demonstrate the salt dissolution process by manipulating a single water molecule at an under-coordinated site of a sodium chloride film. Manipulation of molecule in a controlled manner enables us to understand ion-water interaction as well as dynamics of water molecules at NaCl interfaces, which are responsible for the selective dissolution of anions. The water dipole polarizes the anion in the NaCl ionic crystal, resulting in strong anion-water interaction and weakening of the ionic bonds. Our results provide insights into a simple but important elementary step of the single-ion chemistry, which may be useful in ion-related sciences and technologies.
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Affiliation(s)
- Huijun Han
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Yunjae Park
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Yohan Kim
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Feng Ding
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
- Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen, 518055, China.
| | - Hyung-Joon Shin
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea.
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2
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Zhong Q, Mardyukov A, Solel E, Ebeling D, Schirmeisen A, Schreiner PR. On-Surface Synthesis and Real-Space Visualization of Aromatic P 3 N 3. Angew Chem Int Ed Engl 2023; 62:e202310121. [PMID: 37702299 DOI: 10.1002/anie.202310121] [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: 07/16/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 09/14/2023]
Abstract
On-surface synthesis is at the verge of emerging as the method of choice for the generation and visualization of unstable or unconventional molecules, which could not be obtained via traditional synthetic methods. A case in point is the on-surface synthesis of the structurally elusive cyclotriphosphazene (P3 N3 ), an inorganic aromatic analogue of benzene. Here, we report the preparation of this fleetingly existing species on Cu(111) and Au(111) surfaces at 5.2 K through molecular manipulation with unprecedented precision, i.e., voltage pulse-induced sextuple dechlorination of an ultra-small (about 6 Å) hexachlorophosphazene P3 N3 Cl6 precursor by the tip of a scanning probe microscope. Real-space atomic-level imaging of cyclotriphosphazene reveals its planar D3h -symmetric ring structure. Furthermore, this demasking strategy has been expanded to generate cyclotriphosphazene from a hexaazide precursor P3 N21 via a different stimulation method (photolysis) for complementary measurements by matrix isolation infrared and ultraviolet spectroscopy.
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Affiliation(s)
- Qigang Zhong
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
| | - Artur Mardyukov
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Ephrath Solel
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Daniel Ebeling
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
| | - André Schirmeisen
- Institute of Applied Physics, Justus Liebig University Giessen, Giessen, Germany
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
| | - Peter R Schreiner
- Center for Materials Research (ZfM), Justus Liebig University Giessen, Giessen, Germany
- Institute of Organic Chemistry, Justus Liebig University Giessen, Giessen, Germany
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3
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Cao Y, Mieres-Perez J, Lucht K, Ulrich I, Schweer P, Sanchez-Garcia E, Morgenstern K, Sander W. C-C Coupling of Carbene Molecules on a Metal Surface in the Presence of Water. J Am Chem Soc 2023; 145:11544-11552. [PMID: 37207364 DOI: 10.1021/jacs.2c12274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A novel surface-confined C-C coupling reaction involving two carbene molecules and a water molecule was studied by scanning tunneling microscopy in real space. Carbene fluorenylidene was generated from diazofluorene in the presence of water on a silver surface. While in the absence of water, fluorenylidene covalently binds to the surface to form a surface metal carbene, and water can effectively compete with the silver surface in reacting with the carbene. Water molecules in direct contact with fluorenylidene protonate the carbene to form the fluorenyl cation before the carbene can bind to the surface. In contrast, the surface metal carbene does not react with water. The fluorenyl cation is highly electrophilic and draws electrons from the metal surface to generate the fluorenyl radical which is mobile on the surface at cryogenic temperatures. The final step in this reaction sequence is the reaction of the radical with a remaining fluorenylidene molecule or with diazofluorene to produce the C-C coupling product. Both a water molecule and the metal surface are essential for the consecutive proton and electron transfer followed by C-C coupling. This C-C coupling reaction is unprecedented in solution chemistry.
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Affiliation(s)
- Yunjun Cao
- Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany
| | - Joel Mieres-Perez
- Technische Universität Dortmund, Lehrstuhl für Computational Bioengineering, Dortmund 44227, Germany
| | - Karsten Lucht
- Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany
| | - Iris Ulrich
- Ruhr-Universität Bochum, Lehrstuhl für Organische Chemie II, Universitätsstr. 150, Bochum D-44801, Germany
| | - Paul Schweer
- Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany
| | - Elsa Sanchez-Garcia
- Technische Universität Dortmund, Lehrstuhl für Computational Bioengineering, Dortmund 44227, Germany
| | - Karina Morgenstern
- Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany
| | - Wolfram Sander
- Ruhr-Universität Bochum, Lehrstuhl für Organische Chemie II, Universitätsstr. 150, Bochum D-44801, Germany
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4
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Sloan PA, Rusimova KR. A self-consistent model to link surface electronic band structure to the voltage dependence of hot electron induced molecular nanoprobe experiments. NANOSCALE ADVANCES 2022; 4:4880-4885. [PMID: 36381505 PMCID: PMC9642357 DOI: 10.1039/d2na00644h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
Understanding the ultra-fast transport properties of hot charge carriers is of significant importance both fundamentally and technically in applications like solar cells and transistors. However, direct measurement of charge transport at the relevant nanometre length scales is challenging with only a few experimental methods demonstrated to date. Here we report on molecular nanoprobe experiments on the Si(111)-7 × 7 at room temperature where charge injected from the tip of a scanning tunnelling microscope (STM) travels laterally across a surface and induces single adsorbate toluene molecules to react over length scales of tens of nanometres. A simple model is developed for the fraction of the tunnelling current captured into each of the surface electronic bands with input from only high-resolution scanning tunnelling spectroscopy (STS) of the clean Si(111)-7 × 7 surface. This model is quantitatively linked to the voltage dependence of the molecular nanoprobe experiments through a single manipulation probability (i.e. fitting parameter) per state. This model fits the measured data and gives explanation to the measured voltage onsets, exponential increase in the measured manipulation probabilities and plateau at higher voltages. It also confirms an ultrafast relaxation to the bottom of a surface band for the injected charge after injection, but before the nonlocal spread across the surface.
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Affiliation(s)
- Peter A Sloan
- Department of Physics, University of Bath Bath BA2 7AY UK
- Centre for Nanoscience and Nanotechnology, University of Bath Bath BA2 7AY UK
| | - Kristina R Rusimova
- Department of Physics, University of Bath Bath BA2 7AY UK
- Centre for Nanoscience and Nanotechnology, University of Bath Bath BA2 7AY UK
- Centre for Photonics and Photonic Materials, University of Bath Bath BA2 7AY UK
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5
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Fang W, Meyer Auf der Heide KM, Zaum C, Michaelides A, Morgenstern K. Rapid Water Diffusion at Cryogenic Temperatures through an Inchworm-like Mechanism. NANO LETTERS 2022; 22:340-346. [PMID: 34958578 DOI: 10.1021/acs.nanolett.1c03894] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Water diffusion across the surfaces of materials is of importance to disparate processes such as water purification, ice formation, and more. Despite reports of rapid water diffusion on surfaces the molecular level, details of such processes remain unclear. Here, with scanning tunneling microscopy, we observe structural rearrangements and diffusion of water trimers at unexpectedly low temperatures (<10 K) on a copper surface, temperatures at which water monomers or other clusters do not diffuse. Density functional theory calculations reveal a facile trimer diffusion process involving transformations between elongated and almost cyclic conformers in an inchworm-like manner. These subtle intermolecular reorientations maintain an optimal balance of hydrogen-bonding and water-surface interactions throughout the process. This work shows that the diffusion of hydrogen-bonded clusters can occur at exceedingly low temperatures without the need for hydrogen bond breakage or exchange; findings that will influence Ostwald ripening of ice nanoclusters and hydrogen bonded clusters in general.
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Affiliation(s)
- Wei Fang
- Thomas Young Centre, London Centre for Nanotechnology, and Department of Physics and Astronomy, University College London, London WC1E 6BT, U.K
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
| | | | - Christopher Zaum
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstr. 2, D-30167 Hannover, Germany
| | - Angelos Michaelides
- Thomas Young Centre, London Centre for Nanotechnology, and Department of Physics and Astronomy, University College London, London WC1E 6BT, U.K
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Karina Morgenstern
- Lehrstuhl für physikalische Chemie I, Ruhr-Universität Bochum, Universitätsstr. 150, D-44801 Bochum, Germany
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6
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Zhou G, Huang L. A review of recent advances in computational and experimental analysis of first adsorbed water layer on solid substrate. MOLECULAR SIMULATION 2020. [DOI: 10.1080/08927022.2020.1786086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Guobing Zhou
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK, USA
| | - Liangliang Huang
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK, USA
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7
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Bertram C, Auburger P, Bockstedte M, Stähler J, Bovensiepen U, Morgenstern K. Impact of Electron Solvation on Ice Structures at the Molecular Scale. J Phys Chem Lett 2020; 11:1310-1316. [PMID: 31985230 DOI: 10.1021/acs.jpclett.9b03723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electron attachment and solvation at ice structures are well-known phenomena. The energy liberated in such events is commonly understood to cause temporary changes at such ice structures, but it may also trigger permanent modifications to a yet unknown extent. We determine the impact of electron solvation on D2O structures adsorbed on Cu(111) with low-temperature scanning tunneling microscopy, two-photon photoemission, and ab initio theory. Solvated electrons, generated by ultraviolet photons, lead not only to transient but also to permanent structural changes through the rearrangement of individual molecules. The persistent changes occur near sites with a high density of dangling OD groups that facilitate electron solvation. We conclude that energy dissipation during solvation triggers permanent molecular rearrangement via vibrational excitation.
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Affiliation(s)
- Cord Bertram
- Physical Chemistry I , Ruhr-Universität Bochum , D-44780 Bochum , Germany
- Faculty of Physics , University of Duisburg-Essen , Lotharstr. 1 , D-47048 Duisburg , Germany
| | - Philipp Auburger
- Solid State Theory , Friedrich-Alexander University Erlangen-Nürnberg , Staudtstr. 7B2 , D-91058 Erlangen , Germany
| | - Michel Bockstedte
- Solid State Theory , Friedrich-Alexander University Erlangen-Nürnberg , Staudtstr. 7B2 , D-91058 Erlangen , Germany
- Chemistry and Physics of Materials , University of Salzburg , Jakob-Haringer-Str. 2a , A-5020 Salzburg , Austria
| | - Julia Stähler
- Department of Physical Chemistry , Fritz Haber Institute of the Max Planck Society , Faradayweg 4-6 , D-14195 Berlin , Germany
- Department of Physics , Freie Universität Berlin , Arnimallee 14 , D-14195 Berlin , Germany
| | - Uwe Bovensiepen
- Faculty of Physics , University of Duisburg-Essen , Lotharstr. 1 , D-47048 Duisburg , Germany
- Department of Physics , Freie Universität Berlin , Arnimallee 14 , D-14195 Berlin , Germany
| | - Karina Morgenstern
- Physical Chemistry I , Ruhr-Universität Bochum , D-44780 Bochum , Germany
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8
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Yin Y, Wang J, Wang X, Li S, Jorgensen MR, Ren J, Meng S, Ma L, Schmidt OG. Water nanostructure formation on oxide probed in situ by optical resonances. SCIENCE ADVANCES 2019; 5:eaax6973. [PMID: 31692752 PMCID: PMC6814375 DOI: 10.1126/sciadv.aax6973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 09/14/2019] [Indexed: 05/26/2023]
Abstract
The dynamic characterization of water multilayers on oxide surfaces is hard to achieve by currently available techniques. Despite this, there is an increasing interest in the evolution of water nanostructures on oxides to fully understand the complex dynamics of ice nucleation and growth in natural and artificial environments. Here, we report the in situ detection of the dynamic evolution of nanoscale water layers on an amorphous oxide surface probed by optical resonances. In the water nanolayer growth process, we find an initial nanocluster morphology that turns into a planar layer beyond a critical thickness. In the reverse process, the planar water film converts to nanoclusters, accompanied by a transition from a planar amorphous layer to crystalline nanoclusters. Our results are explained by a simple thermodynamic model as well as kinetic considerations. Our work represents an approach to reveal the nanostructure and dynamics at the water-oxide interface using resonant light probing.
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Affiliation(s)
- Yin Yin
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - Jiawei Wang
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer Str. 70, 09107 Chemnitz, Germany
| | - Xiaoxia Wang
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - Shilong Li
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - Matthew R. Jorgensen
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - Junfeng Ren
- School of Physics and Electronics, Shandong Normal University, 250014 Jinan, China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Libo Ma
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - Oliver G. Schmidt
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer Str. 70, 09107 Chemnitz, Germany
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Rosenbergstraße 6, TU Chemnitz, 09126 Chemnitz, Germany
- Nanophysics, Faculty of Physics, TU Dresden, 01062 Dresden, Germany
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9
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Dong A, Yan L, Sun L, Yan S, Shan X, Guo Y, Meng S, Lu X. Identifying Few-Molecule Water Clusters with High Precision on Au(111) Surface. ACS NANO 2018; 12:6452-6457. [PMID: 29812905 DOI: 10.1021/acsnano.8b02264] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Revealing the nature of a hydrogen-bond network in water structures is one of the imperative objectives of science. With the use of a low-temperature scanning tunneling microscope, water clusters on a Au(111) surface were directly imaged with molecular resolution by a functionalized tip. The internal structures of the water clusters as well as the geometry variations with the increase of size were identified. In contrast to a buckled water hexamer predicted by previous theoretical calculations, our results present deterministic evidence for a flat configuration of water hexamers on Au(111), corroborated by density functional theory calculations with properly implemented van der Waals corrections. The consistency between the experimental observations and improved theoretical calculations not only renders the internal structures of absorbed water clusters unambiguously, but also directly manifests the crucial role of van der Waals interactions in constructing water-solid interfaces.
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Affiliation(s)
- Anning Dong
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
| | - Lei Yan
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
| | - Lihuan Sun
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
| | - Shichao Yan
- School of Physical Science and Technology , ShanghaiTech University , Shanghai , 201210 , China
| | - Xinyan Shan
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
| | - Yang Guo
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
| | - Sheng Meng
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing , 100190 , People's Republic of China
| | - Xinghua Lu
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics , Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing , 100190 , People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing , 100190 , People's Republic of China
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10
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The effect of hydration number on the interfacial transport of sodium ions. Nature 2018; 557:701-705. [DOI: 10.1038/s41586-018-0122-2] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 03/05/2018] [Indexed: 11/08/2022]
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11
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Guo J, Bian K, Lin Z, Jiang Y. Perspective: Structure and dynamics of water at surfaces probed by scanning tunneling microscopy and spectroscopy. J Chem Phys 2017; 145:160901. [PMID: 27802647 DOI: 10.1063/1.4964668] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The detailed and precise understanding of water-solid interaction largely relies on the development of atomic-scale experimental techniques, among which scanning tunneling microscopy (STM) has proven to be a noteworthy example. In this perspective, we review the recent advances of STM techniques in imaging, spectroscopy, and manipulation of water molecules. We discuss how those newly developed techniques are applied to probe the structure and dynamics of water at solid surfaces with single-molecule and even submolecular resolution, paying particular attention to the ability of accessing the degree of freedom of hydrogen. In the end, we present an outlook on the directions of future STM studies of water-solid interfaces as well as the challenges faced by this field. Some new scanning probe techniques beyond STM are also envisaged.
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Affiliation(s)
- Jing Guo
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Ke Bian
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Zeren Lin
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Ying Jiang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
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12
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Rusimova KR, Bannister N, Harrison P, Lock D, Crampin S, Palmer RE, Sloan PA. Initiating and imaging the coherent surface dynamics of charge carriers in real space. Nat Commun 2016; 7:12839. [PMID: 27677938 PMCID: PMC5052722 DOI: 10.1038/ncomms12839] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 08/05/2016] [Indexed: 11/09/2022] Open
Abstract
The tip of a scanning tunnelling microscope is an atomic-scale source of electrons and holes. As the injected charge spreads out, it can induce adsorbed molecules to react. By comparing large-scale 'before' and 'after' images of an adsorbate covered surface, the spatial extent of the nonlocal manipulation is revealed. Here, we measure the nonlocal manipulation of toluene molecules on the Si(111)-7 × 7 surface at room temperature. Both the range and probability of nonlocal manipulation have a voltage dependence. A region within 5-15 nm of the injection site shows a marked reduction in manipulation. We propose that this region marks the extent of the initial coherent (that is, ballistic) time-dependent evolution of the injected charge carrier. Using scanning tunnelling spectroscopy, we develop a model of this time-dependent expansion of the initially localized hole wavepacket within a particular surface state and deduce a quantum coherence (ballistic) lifetime of ∼10 fs.
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Affiliation(s)
- K R Rusimova
- Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Bath BA2 7AY, UK.,Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK
| | - N Bannister
- Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Bath BA2 7AY, UK
| | - P Harrison
- Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Bath BA2 7AY, UK
| | - D Lock
- Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Bath BA2 7AY, UK
| | - S Crampin
- Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Bath BA2 7AY, UK
| | - R E Palmer
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK
| | - P A Sloan
- Centre for Nanoscience and Nanotechnology, Department of Physics, University of Bath, Bath BA2 7AY, UK
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13
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Simic-Milosevic V, Mehlhorn M, Morgenstern K. Imaging the Bonds of Dehalogenated Benzene Radicals on Cu(111) and Au(111). Chemphyschem 2016; 17:2679-85. [PMID: 27272737 DOI: 10.1002/cphc.201600495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Indexed: 11/07/2022]
Abstract
Dissociative adsorption of doubly substituted benzene molecules leads to formation of benzyne radicals. In this study, co-adsorbed hydrogen molecules are used in scanning tunneling hydrogen microscopy to enhance the contrast of the meta- and the para-isomers of these radicals on Cu(111) and Au(111). Up to three hydrogen molecules are attached to one radical. One hydrogen molecule reveals the orientation of the carbon ring and its adsorption site, allowing discrimination between the two radicals. Two hydrogen molecules reflect the bond picture of the carbon skeleton and reveals that adsorption on Cu(111) distorts the meta- isomer differently from its gas-phase distortion. Three hydrogen molecules allow us to determine the bond picture of a minor species.
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Affiliation(s)
| | - Michael Mehlhorn
- Institut für Experimentalphysik, FU Berlin, Arnimallee 14, D-14195, Berlin, Germany
| | - Karina Morgenstern
- Institut für Experimentalphysik, FU Berlin, Arnimallee 14, D-14195, Berlin, Germany. .,Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, D-44780, Bochum, Germany.
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14
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Guo Y, Ding Z, Sun L, Li J, Meng S, Lu X. Inducing Transient Charge State of a Single Water Cluster on Cu(111) Surface. ACS NANO 2016; 10:4489-4495. [PMID: 27007702 DOI: 10.1021/acsnano.6b00230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The hydrated electron on solid surface is a crucial species to interfacial chemistry. We present a joint low-temperature scanning tunneling microscopy and density functional theory investigation to explore the existence of a transient hydrated electron state induced by injecting tunneling electrons into a single water nonamer cluster on Cu(111) surface. The directional diffusion of water cluster under the Coulomb repulsive potential has been observed as evidence for the emergence of the transient hydrated electron. A critical structure transformation in water cluster for the emergence of hydrated electron has been identified. A charging mechanism has been proposed based on density functional theory calculation and scanning tunneling microscope results.
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Affiliation(s)
- Yang Guo
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Zijing Ding
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Lihuan Sun
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Jianmei Li
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Sheng Meng
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
- Collaborative Innovation Center of Quantum Matter , Beijing 100190, People's Republic of China
| | - Xinghua Lu
- Beijing National Laboratory for Condensed-Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
- Collaborative Innovation Center of Quantum Matter , Beijing 100190, People's Republic of China
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15
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Liriano ML, Carrasco J, Lewis EA, Murphy CJ, Lawton TJ, Marcinkowski MD, Therrien AJ, Michaelides A, Sykes ECH. The interplay of covalency, hydrogen bonding, and dispersion leads to a long range chiral network: The example of 2-butanol. J Chem Phys 2016; 144:094703. [DOI: 10.1063/1.4941560] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Melissa L. Liriano
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA
| | - Javier Carrasco
- CIC Energigune, Albert Einstein 48, 01510 Miñano, Álava, Spain
| | - Emily A. Lewis
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA
| | - Colin J. Murphy
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA
| | - Timothy J. Lawton
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA
| | | | - Andrew J. Therrien
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA
| | - Angelos Michaelides
- Thomas Young Centre, London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - E. Charles H. Sykes
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA
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16
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Lock D, Rusimova KR, Pan TL, Palmer RE, Sloan PA. Atomically resolved real-space imaging of hot electron dynamics. Nat Commun 2015; 6:8365. [PMID: 26387703 PMCID: PMC4595757 DOI: 10.1038/ncomms9365] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/10/2015] [Indexed: 11/24/2022] Open
Abstract
The dynamics of hot electrons are central to understanding the properties of many electronic devices. But their ultra-short lifetime, typically 100 fs or less, and correspondingly short transport length-scale in the nanometre range constrain real-space investigations. Here we report variable temperature and voltage measurements of the nonlocal manipulation of adsorbed molecules on the Si(111)-7 × 7 surface in the scanning tunnelling microscope. The range of the nonlocal effect increases with temperature and, at constant temperature, is invariant over a wide range of electron energies. The measurements probe, in real space, the underlying hot electron dynamics on the 10 nm scale and are well described by a two-dimensional diffusive model with a single decay channel, consistent with 2-photon photo-emission (2PPE) measurements of the real time dynamics.
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Affiliation(s)
- D. Lock
- Department of Physics, University of Bath, Bath, BA2 7AY, UK
| | - K. R. Rusimova
- Department of Physics, University of Bath, Bath, BA2 7AY, UK
| | - T. L. Pan
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
| | - R. E. Palmer
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
| | - P. A. Sloan
- Department of Physics, University of Bath, Bath, BA2 7AY, UK
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17
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Huang L, Gubbins KE, Li L, Lu X. Water on titanium dioxide surface: a revisiting by reactive molecular dynamics simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:14832-14840. [PMID: 25423593 DOI: 10.1021/la5037426] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The behavior of surface water, especially the adsorption and dissociation characteristics, is a key to understanding and promoting photocatalytic and biomedical applications of titanium dioxide materials. Using molecular dynamics simulations with the ReaxFF force field, we study the interactions between water and five different TiO2 surfaces that are of interest to both experiments and theoretical calculations. The results show that TiO2 surfaces demonstrate different reactivities for water dissociation [rutile (011) > TiO2-B (100) > anatase (001) > rutile (110)], and there is no water dissociation observed on the TiO2-B (001) surface. The simulations also reveal that the water dissociation and the TiO2 surface chemistry change, and the new surface Ti-OH and O-H functional groups affect the orientation of other near-surface water molecules. On the reactive surface, such as the rutile (110) surface, water dissociated and formed new Ti-OH and O-H bonds on the surface. Those functional groups enhanced the hydrogen bond networking with the near-surface water molecules and their configurations. On the nonreactive TiO2-B (001) surface where no molecular or dissociative water adsorption is observed, near-surface water can also form hydrogen bonds with surface oxygen atoms of TiO2, but their distance to the surface is longer than that on the rutile (011) surface.
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Affiliation(s)
- Liangliang Huang
- School of Chemical, Biological and Materials Engineering, University of Oklahoma , Norman, Oklahoma 73019, United States
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18
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Sun Q, Xu W. Regulating the Interactions of Adsorbates on Surfaces by Scanning Tunneling Microscopy Manipulation. Chemphyschem 2014; 15:2657-63. [DOI: 10.1002/cphc.201402021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Indexed: 11/05/2022]
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19
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Hahn JR, Jang SH, Kim KW, Son SB. Hot carrier-selective chemical reactions on Ag(110). J Chem Phys 2013; 139:074707. [PMID: 23968107 DOI: 10.1063/1.4817947] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Here, we show that the pathways, products, and efficiencies of reactions occurring on a metal surface can be spatially modulated by varying the type and energy of hot carriers produced by injecting tunneling electrons or holes from a scanning tunneling microscope tip into the metal surface. Control over the metal surface reactions was demonstrated for the large-scale dissociation reaction of O2 molecules on a Ag(110) surface. Hot electrons (or holes) transported through the metal surface to chemisorbed O2 selectively dissociated the molecule into two oxygen atoms separated along the [110] (or [001]) lattice direction. The reaction selectivity was enhanced compared to the selectivity of a direct reaction involving tunneling carriers.
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Affiliation(s)
- Jae Ryang Hahn
- Department of Chemistry and Bioactive Materials Science and Research Institute of Physics and Chemistry, Chonbuk National University, Jeonju 561-756, Korea.
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20
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Henzl J, Boom K, Morgenstern K. Reorientation of a single bond within an adsorbed molecule by tunneling electrons. J Am Chem Soc 2013; 135:11501-4. [PMID: 23895214 DOI: 10.1021/ja405809f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Scanning tunneling microscopy offers the exciting possibility to manipulate individual molecules by vibrational excitation via inelastically tunneling electrons. The electrons transfer energy into molecular vibrational modes, leading to breakage or formation of individual bonds. It is challenging to precisely control intramolecular changes by this process. We demonstrate that for 4,4'-dihydroxyazobenzene adsorbed on Au(111) or Ag(111), the manipulation facilitates rotation of the OH end groups around the C-O bond between metastable states; this corresponds to a reorientation of the hydrogen, the ultimate limit of a conformational change within a molecule.
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Affiliation(s)
- Jörg Henzl
- Abteilung für Atomare und Molekulare Strukturen (ATMOS), Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstr. 2, D-30167 Hannover, Germany
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21
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Mehlhorn M, Schnur S, Groß A, Morgenstern K. Molecular-Scale Imaging of Water Near Charged Surfaces. ChemElectroChem 2013. [DOI: 10.1002/celc.201300063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Jiang Y, Huan Q, Fabris L, Bazan GC, Ho W. Submolecular control, spectroscopy and imaging of bond-selective chemistry in single functionalized molecules. Nat Chem 2012; 5:36-41. [DOI: 10.1038/nchem.1488] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 09/26/2012] [Indexed: 12/22/2022]
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23
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Carrasco J, Hodgson A, Michaelides A. A molecular perspective of water at metal interfaces. NATURE MATERIALS 2012; 11:667-74. [PMID: 22825022 DOI: 10.1038/nmat3354] [Citation(s) in RCA: 362] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Water/solid interfaces are relevant to a broad range of physicochemical phenomena and technological processes such as corrosion, lubrication, heterogeneous catalysis and electrochemistry. Although many fields have contributed to rapid progress in the fundamental knowledge of water at interfaces, detailed molecular-level understanding of water/solid interfaces comes mainly from studies on flat metal substrates. These studies have recently shown that a remarkably rich variety of structures form at the interface between water and even seemingly simple flat surfaces. In this Review we discuss the most exciting work in this area, in particular the emerging physical insight and general concepts about how water binds to metal surfaces. We also provide a perspective on outstanding problems, challenges and open questions.
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Affiliation(s)
- Javier Carrasco
- Instituto de Catálisis y Petroleoquímica, CSIC, Marie Curie 2, E-28049 Madrid, Spain
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24
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He KT, Wood JD, Doidge GP, Pop E, Lyding JW. Scanning tunneling microscopy study and nanomanipulation of graphene-coated water on mica. NANO LETTERS 2012; 12:2665-72. [PMID: 22612064 DOI: 10.1021/nl202613t] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We study interfacial water trapped between a sheet of graphene and a muscovite (mica) surface using Raman spectroscopy and ultrahigh vacuum scanning tunneling microscopy (UHV-STM) at room temperature. We are able to image the graphene-water interface with atomic resolution, revealing a layered network of water trapped underneath the graphene. We identify water layer numbers with a carbon nanotube height reference. Under normal scanning conditions, the water structures remain stable. However, at greater electron energies, we are able to locally manipulate the water using the STM tip.
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Affiliation(s)
- Kevin T He
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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25
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Lawton TJ, Carrasco J, Baber AE, Michaelides A, Sykes ECH. Visualization of hydrogen bonding and associated chirality in methanol hexamers. PHYSICAL REVIEW LETTERS 2011; 107:256101. [PMID: 22243093 DOI: 10.1103/physrevlett.107.256101] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 10/13/2011] [Indexed: 05/31/2023]
Abstract
Using a combination of scanning tunneling microscopy (STM) and density functional theory the hydrogen bond directionality and associated chirality of enantiopure clusters is visualized and controlled. This is demonstrated with methanol hexamers adsorbed on Au(111), which depending on their chirality, adopt two distinct molecular footprints on the surface. Controlled STM tip manipulations were used to interconvert the chirality of entire clusters and to break up metastable chain structures into hexamers.
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Affiliation(s)
- Timothy J Lawton
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155-5813, USA
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26
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Forster M, Raval R, Hodgson A, Carrasco J, Michaelides A. c(2×2) water-hydroxyl layer on Cu(110): a wetting layer stabilized by Bjerrum defects. PHYSICAL REVIEW LETTERS 2011; 106:046103. [PMID: 21405340 DOI: 10.1103/physrevlett.106.046103] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Indexed: 05/30/2023]
Abstract
Understanding the composition and stability of mixed water-hydroxyl layers is a key step in describing wetting and how surfaces respond to redox processes. Here we show that, instead of forming a complete hydrogen bonding network, structures containing an excess of water over hydroxyl are stabilized on Cu(110) by forming a distorted hexagonal network of water-hydroxyl trimers containing Bjerrum defects. This arrangement maximizes the number of strong bonds formed by water donation to OH and provides uncoordinated OH groups able to hydrogen bond multilayer water and nucleate growth.
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Affiliation(s)
- Matthew Forster
- Surface Science Research Centre, University of Liverpool, Liverpool, United Kingdom
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27
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Russell SM, Liu DJ, Kawai M, Kim Y, Thiel PA. Low-temperature adsorption of H2S on Ag(111). J Chem Phys 2010; 133:124705. [PMID: 20886963 DOI: 10.1063/1.3481481] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
H(2)S forms a rich variety of structures on Ag(111) at low temperature and submonolayer coverage. The molecules decorate step edges, exist as isolated entities on terraces, and aggregate into clusters and islands, under various conditions. One type of island exhibits a (√37×√37)R25.3° unit cell. Typically, molecules in the clusters and islands are separated by about 0.4 nm, the same as the S-S separation in crystalline H(2)S. Density functional theory indicates that hydrogen-bonded clusters contain two types of molecules. One is very similar to an isolated adsorbed H(2)S molecule, with both S-H bonds nearly parallel to the surface. The other has a S-H bond pointed toward the surface. The potential energy surface for adsorption and diffusion is very smooth.
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Affiliation(s)
- Selena M Russell
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
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28
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Sloan PA, Sakulsermsuk S, Palmer RE. Nonlocal desorption of chlorobenzene molecules from the Si(111)-(7×7) surface by charge injection from the tip of a scanning tunneling microscope: remote control of atomic manipulation. PHYSICAL REVIEW LETTERS 2010; 105:048301. [PMID: 20867889 DOI: 10.1103/physrevlett.105.048301] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Indexed: 05/29/2023]
Abstract
We report the nonlocal desorption of chlorobenzene molecules from the Si(111)-(7×7) surface by charge injection from the laterally distant tip of a scanning tunneling microscope and demonstrate remote control of the manipulation process by precise selection of the atomic site for injection. Nonlocal desorption decays exponentially as a function of radial distance (decay length ∼100 A) from the injection site. Electron injection at corner-hole and faulted middle adatoms sites couples preferentially to the desorption of distant adsorbate molecules. Molecules on the faulted half of the unit cell desorb with higher probability than those on the unfaulted half.
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Affiliation(s)
- P A Sloan
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, United Kingdom
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29
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Hu XL, Klimeš J, Michaelides A. Proton transfer in adsorbed water dimers. Phys Chem Chem Phys 2010; 12:3953-6. [DOI: 10.1039/b924422k] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Tomatsu K, Nakatsuji K, Yamada M, Komori F, Yan B, Yam C, Frauenheim T, Xu Y, Duan W. Local vibrational excitation through extended electronic states at a germanium surface. PHYSICAL REVIEW LETTERS 2009; 103:266102. [PMID: 20366323 DOI: 10.1103/physrevlett.103.266102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Indexed: 05/29/2023]
Abstract
Atomic motion through excitation of extended surface electronic states on Ge(001) is studied using extraction of electrons by scanning tunneling microscopy and density functional theory. Single-electron excitation into the surface states nonlocally alters the tilting orientation of the surface Ge dimer, and the change rate depends on the excitation energy. Theoretical investigations identify the excited electronic states for the dimer motion, and clarify the strong coupling between the surface state electrons and a local vibrational mode of the dimer for changing the tilting orientation.
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Affiliation(s)
- Kota Tomatsu
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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31
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Wang C, Lu H, Wang Z, Xiu P, Zhou B, Zuo G, Wan R, Hu J, Fang H. Stable liquid water droplet on a water monolayer formed at room temperature on ionic model substrates. PHYSICAL REVIEW LETTERS 2009; 103:137801. [PMID: 19905541 DOI: 10.1103/physrevlett.103.137801] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Indexed: 05/28/2023]
Abstract
Using molecular dynamics simulation, we show direct evidence of the unexpected phenomenon of "water that does not wet a water monolayer" at room temperature. This phenomenon is attributed to the structure of the water beneath the water droplet, which exhibits an ordered water monolayer. Remarkably, there remains a considerable number of dangling OH bonds in this room temperature water monolayer, in contrast with the absence of dangling OH bonds at cryogenic temperature.
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Affiliation(s)
- Chunlei Wang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China
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32
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Abstract
Molecular switches occur throughout nature. In one prominent example, light induces the isomerization of retinal from the compact 11-cis form to the elongated all-trans form, a conversion that triggers the transformation of light into a neural impulse in the eye. Applying these natural principles to synthetic systems offers a promising way to construct smaller and faster nanoelectronic devices. In such systems, electronic switches are essential components for storage and logical operations. The development of molecular switches on the single-molecule level would represent a major step toward incorporating molecules as building units into nanoelectronic circuits. Molecular switches must be both reversible and bistable. To meet these requirements, a molecule must have at least two different thermally stable forms and a way to repeatedly interconvert between those forms based on changes in light, heat, pressure, magnetic or electric fields, pH, mechanical forces, or electric currents. The conversion should be connected to a measurable change in electronic, optical, magnetic, or mechanical properties. Because isomers can differ significantly in physical and chemical properties, isomerization could serve as a molecular switching mechanism. Integration of molecular switches into larger circuits will probably require arranging them on surfaces, which will require a better understanding of isomerization reactions in these environments. In this Account, we describe our scanning tunneling microscopy studies of the isomerization of individual molecules adsorbed on metal surfaces. Investigating chlorobenzene and azobenzene derivatives on the fcc(111) faces of Ag, Cu, and Au, we explored the influence of substituents and the substrate on the excitation mechanism of the isomerization reaction induced by inelastically tunneling electrons. We achieved an irreversible configurational (cis-trans) isomerization of individual 4-dimethyl-amino-azobenzene-4-sulfonic acid molecules on Au(111), a reversible configurational (cis-trans) isomerization of amino-nitro-azobenzene on Au(111), a constitutional (meta-ortho) isomerization of chloronitrobenzene molecules adsorbed on Cu(111) and Au(111), and a constitutional (meta-para) isomerization of dichlorobenzene molecules adsorbed on Cu(111) and Ag(111). These studies demonstrate that we can induce a variety of isomerization reactions by electron excitation on a metal surface. Our model isomerization studies provide a way to manipulate properties of single molecules, changing both their geometric structure and their physicochemical properties. The control of isomerization of single molecules will advance the development of single-molecule electronics and other nanoscale processes.
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Affiliation(s)
- Karina Morgenstern
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstrasse 2, D-30167 Hannover, Germany
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