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Mendis KC, Li X, Valdiviezo J, Banziger SD, Zhang P, Ren T, Beratan DN, Rubtsov IV. Electron transfer rate modulation with mid-IR in butadiyne-bridged donor-bridge-acceptor compounds. Phys Chem Chem Phys 2024; 26:1819-1828. [PMID: 38168814 DOI: 10.1039/d3cp03175f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Controlling electron transfer (ET) processes in donor-bridge-acceptor (DBA) compounds by mid-IR excitation can enhance our understanding of the ET dynamics and may find practical applications in molecular sensing and molecular-scale electronics. Alkyne moieties are attractive to serve as ET bridges, as they offer the possibility of fast ET and present convenient vibrational modes to perturb the ET dynamics. Yet, these bridges introduce complexity because of the strong torsion angle dependence of the ET rates and transition dipoles among electronic states and a shallow torsion barrier. In this study, we implemented ultrafast 3-pulse laser spectroscopy to investigate how the ET from the dimethyl aniline (D) electron donor to the N-isopropyl-1,8-napthalimide (NAP) electron acceptor can be altered by exciting the CC stretching mode (νCC) of the butadiyne bridge linking the donor and acceptor. The electron transfer was initiated by electronically exciting the acceptor moiety at 400 nm, followed by vibrational excitation of the alkyne, νCC, and detecting the changes in the absorption spectrum in the visible spectral region. The experiments were performed at different delay times t1 and t2, which are the delays between UV-mid-IR and mid-IR-Vis pulses, respectively. Two sets of torsion-angle conformers were identified, one featuring a very fast mean ET time of 0.63 ps (group A) and another featuring a slower mean ET time of 4.3 ps (group B), in the absence of the mid-IR excitation. TD-DFT calculations were performed to determine key torsion angle dependent molecular parameters, including the electronic and vibrational transition dipoles, transition frequencies, and electronic couplings. To describe the 3-pulse data, we developed a kinetic model that includes a locally excited, acceptor-based S2 state, a charge separated S1 state, and their vibrationally excited counterparts, with either excited νCC (denoted as S1Atr, S1Btr, S2Atr, and S2Btr, where tr stands for the excited triplet bond, νCC) or excited daughter modes of the νCC relaxation (S1Ah, S1Bh, S2Ah, and S2Bh, where h stands for vibrationally hot species). The kinetic model was solved analytically, and the species-associated spectra (SAS) were determined numerically using a matrix approach, treating first the experiments with longer t1 delays and then using the already determined SAS for modeling the experiments with shorter t1 delays. Strong vibronic coupling of νCC and of vibrationally hot states makes the analysis complicated. Nevertheless, the SAS were identified and the ET rates of the vibrationally excited species, S2Atr, S2Btr and S2Bh, were determined. The results show that the ET rate for the S2A species is ca. 1.2-fold slower when the νCC mode is excited. The ET rate for species S2B is slower by ca. 1.3-fold if the compound is vibrationally hot and is essentially unchanged when the νCC mode is excited. The SAS determined for the tr and h species resemble the SAS for their respective precursor species in the 2-pulse transient absorption experiments, which validates the procedure used and the results.
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Affiliation(s)
- Kasun C Mendis
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
| | - Xiao Li
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
| | - Jesús Valdiviezo
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Susannah D Banziger
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Peng Zhang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Tong Ren
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - David N Beratan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Department of Biochemistry, Duke University, Durham, North Carolina 27710, USA
| | - Igor V Rubtsov
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
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Pechenezhskiy IV, Hong X, Nguyen GD, Dahl JEP, Carlson RMK, Wang F, Crommie MF. Infrared spectroscopy of molecular submonolayers on surfaces by infrared scanning tunneling microscopy: tetramantane on Au111. PHYSICAL REVIEW LETTERS 2013; 111:126101. [PMID: 24093277 DOI: 10.1103/physrevlett.111.126101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Indexed: 06/02/2023]
Abstract
We have developed a new scanning-tunneling-microscopy-based spectroscopy technique to characterize infrared (IR) absorption of submonolayers of molecules on conducting crystals. The technique employs a scanning tunneling microscope as a precise detector to measure the expansion of a molecule-decorated crystal that is irradiated by IR light from a tunable laser source. Using this technique, we obtain the IR absorption spectra of [121]tetramantane and [123]tetramantane on Au(111). Significant differences between the IR spectra for these two isomers show the power of this new technique to differentiate chemical structures even when single-molecule-resolved scanning tunneling microscopy (STM) images look quite similar. Furthermore, the new technique was found to yield significantly better spectral resolution than STM-based inelastic electron tunneling spectroscopy, and to allow determination of optical absorption cross sections. Compared to IR spectroscopy of bulk tetramantane powders, infrared scanning tunneling microscopy (IRSTM) spectra reveal narrower and blueshifted vibrational peaks for an ordered tetramantane adlayer. Differences between bulk and surface tetramantane vibrational spectra are explained via molecule-molecule interactions.
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Affiliation(s)
- Ivan V Pechenezhskiy
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Burema SR, Bocquet ML. Resonance Charges to Encode Selection Rules in Inelastic Electron Tunneling Spectroscopy. J Phys Chem Lett 2012; 3:3007-3011. [PMID: 26292242 DOI: 10.1021/jz3012832] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
From extensive simulations of a set of covalently grafted phenyl derivatives onto Cu(111), we derive a simplistic rule that selectively predicts the onset of stretching vibrations in inelastic electron tunneling spectroscopy (IETS) with the scanning tunneling microscope. Indeed the rise (extinction) of the highest-frequency modes is found to correlate to the accumulation (depletion) of π electron density at the metal-organic contact point. This π electron density can be fine-tuned by the usage of (de) activating aromatic substituent at different ring positions. This finding provides a simple analysis tool that can be used to reveal structural characteristics on the atomic scale by IETS.
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Affiliation(s)
- Shiri R Burema
- Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, CNRS UMR 5182, 46 Allée d'Italie, 69364 CEDEX07 Lyon, France
| | - Marie-Laure Bocquet
- Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, CNRS UMR 5182, 46 Allée d'Italie, 69364 CEDEX07 Lyon, France
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Burema SR, Bocquet ML. Sensitizers in inelastic electron tunneling spectroscopy: a first-principles study of functional aromatics on Cu(111). NANOTECHNOLOGY 2012; 23:315702. [PMID: 22797417 DOI: 10.1088/0957-4484/23/31/315702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Low sensitivity is a key problem in inelastic electron tunneling spectroscopy (IETS) with the scanning tunneling microscope. Using first-principles simulations, we predict different means to tune the IETS sensitivity of symmetrical functional aromatics on a Cu(111) surface. We show how the IET-spectra of phenyl-NO₂ compounds can be greatly enhanced as compared to pristine phenyl. More precisely, the NO₂ substituent qualifies as a sensitizer of low-frequency wagging modes, but also as a quencher of high-frequency stretching modes. At variance, the CO₂ substituent is found to suppress the whole IET-activity. The head-up (non-anchoring) and head-down (anchoring) configurations of the functional group lead to minor changes in the signals, nevertheless allowing access to discriminate configurational features. It is shown how to disentangle the electronic and steric effects of the substituent in the STM junction.
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Affiliation(s)
- S R Burema
- Laboratoire de Chimie, Ecole Normale Supérieure de Lyon, Université de Lyon, CNRS, France
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Morgenstern K. On the interpretation of IETS spectra of a small organic molecule. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:484007. [PMID: 22086063 DOI: 10.1088/0953-8984/23/48/484007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have investigated vibrational spectra of nitrobenzene molecules adsorbed on Cu(111) by low temperature inelastic electron tunneling spectroscopy. This molecule, which should support 39 internal modes, only gives rise to seven peaks in the spectra. We outline a comparison with ensemble IR data and interpret the small number of vibrational peaks by the superposition of a multitude of almost isoenergetic vibrational modes. The non-detectability of further modes cannot be understood in terms of symmetry considerations. Additional modes in the spectra are attributed to external molecular-metal vibrations.
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Affiliation(s)
- Karina Morgenstern
- Institut für Festkörperphysik, Abteilung ATMOS, Leibniz Universität Hannover, Hannover, Germany
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Carias H, Beratan DN, Skourtis SS. Floquet Analysis for Vibronically Modulated Electron Tunneling. J Phys Chem B 2011; 115:5510-8. [DOI: 10.1021/jp111097a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Horacio Carias
- Department of Physics, Duke University, Durham, North Carolina 27708, United States
| | - David N. Beratan
- Departments of Chemistry, Biochemistry, and Physics, Duke University, Durham, North Carolina 27708, United States
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Abstract
Central to the view of electron-transfer reactions is the idea that nuclear motion generates a transition state geometry at which the electron/hole amplitude propagates coherently from the electron donor to the electron acceptor. In the weakly coupled or nonadiabatic regime, the electron amplitude tunnels through an electronic barrier between the donor and acceptor. The structure of the barrier is determined by the covalent and noncovalent interactions of the bridge. Because the tunneling barrier depends on the nuclear coordinates of the reactants (and on the surrounding medium), the tunneling barrier is highly anisotropic, and it is useful to identify particular routes, or pathways, along which the transmission amplitude propagates. Moreover, when more than one such pathway exists, and the paths give rise to comparable transmission amplitude magnitudes, one may expect to observe quantum interferences among pathways if the propagation remains coherent. Given that the effective tunneling barrier height and width are affected by the nuclear positions, the modulation of the nuclear coordinates will lead to a modulation of the tunneling barrier and hence of the electron flow. For long distance electron transfer in biological and biomimetic systems, nuclear fluctuations, arising from flexible protein moieties and mobile water bridges, can become quite significant. We discuss experimental and theoretical results that explore the quantum interferences among coupling pathways in electron-transfer kinetics; we emphasize recent data and theories associated with the signatures of chirality and inelastic processes, which are manifested in the tunneling pathway coherence (or absence of coherence).
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Abstract
Central to theories of electron transfer (ET) is the idea that nuclear motion generates a transition state that enables electron flow to proceed, but nuclear motion also induces fluctuations in the donor-acceptor (DA) electronic coupling that is the rate-limiting parameter for nonadiabatic ET. The interplay between the DA energy gap and DA coupling fluctuations is particularly noteworthy in biological ET, where flexible protein and mobile water bridges take center stage. Here, we discuss the critical timescales at play for ET reactions in fluctuating media, highlighting issues of the Condon approximation, average medium versus fluctuation-controlled electron tunneling, gated and solvent relaxation controlled electron transfer, and the influence of inelastic tunneling on electronic coupling pathway interferences. Taken together, one may use this framework to establish principles to describe how macromolecular structure and structural fluctuations influence ET reactions. This framework deepens our understanding of ET chemistry in fluctuating media. Moreover, it provides a unifying perspective for biophysical charge-transfer processes and helps to frame new questions associated with energy harvesting and transduction in fluctuating media.
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Affiliation(s)
| | - David H. Waldeck
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260;
| | - David N. Beratan
- Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708;
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Lin Z, Lawrence CM, Xiao D, Kireev VV, Skourtis SS, Sessler JL, Beratan DN, Rubtsov IV. Modulating Unimolecular Charge Transfer by Exciting Bridge Vibrations. J Am Chem Soc 2009; 131:18060-2. [DOI: 10.1021/ja907041t] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Zhiwei Lin
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, 78712, and Department of Physics, University of Cyprus, Nicosia 1678, Cyprus
| | - Candace M. Lawrence
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, 78712, and Department of Physics, University of Cyprus, Nicosia 1678, Cyprus
| | - Dequan Xiao
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, 78712, and Department of Physics, University of Cyprus, Nicosia 1678, Cyprus
| | - Victor V. Kireev
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, 78712, and Department of Physics, University of Cyprus, Nicosia 1678, Cyprus
| | - Spiros S. Skourtis
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, 78712, and Department of Physics, University of Cyprus, Nicosia 1678, Cyprus
| | - Jonathan L. Sessler
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, 78712, and Department of Physics, University of Cyprus, Nicosia 1678, Cyprus
| | - David N. Beratan
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, 78712, and Department of Physics, University of Cyprus, Nicosia 1678, Cyprus
| | - Igor V. Rubtsov
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas, 78712, and Department of Physics, University of Cyprus, Nicosia 1678, Cyprus
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Beratan DN, Skourtis SS, Balabin IA, Balaeff A, Keinan S, Venkatramani R, Xiao D. Steering electrons on moving pathways. Acc Chem Res 2009; 42:1669-78. [PMID: 19645446 DOI: 10.1021/ar900123t] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Electron transfer (ET) reactions provide a nexus among chemistry, biochemistry, and physics. These reactions underpin the "power plants" and "power grids" of bioenergetics, and they challenge us to understand how evolution manipulates structure to control ET kinetics. Ball-and-stick models for the machinery of electron transfer, however, fail to capture the rich electronic and nuclear dynamics of ET molecules: these static representations disguise, for example, the range of thermally accessible molecular conformations. The influence of structural fluctuations on electron-transfer kinetics is amplified by the exponential decay of electron tunneling probabilities with distance, as well as the delicate interference among coupling pathways. Fluctuations in the surrounding medium can also switch transport between coherent and incoherent ET mechanisms--and may gate ET so that its kinetics is limited by conformational interconversion times, rather than by the intrinsic ET time scale. Moreover, preparation of a charge-polarized donor state or of a donor state with linear or angular momentum can have profound dynamical and kinetic consequences. In this Account, we establish a vocabulary to describe how the conformational ensemble and the prepared donor state influence ET kinetics in macromolecules. This framework is helping to unravel the richness of functional biological ET pathways, which have evolved within fluctuating macromolecular structures. The conceptual framework for describing nonadiabatic ET seems disarmingly simple: compute the ensemble-averaged (mean-squared) donor-acceptor (DA) tunneling interaction, <H(DA)(2)>, and the Franck-Condon weighted density of states, rho(FC), to describe the rate, (2pi/variant Planck's over 2pi)<H(DA)(2)>rho(FC). Modern descriptions of the thermally averaged electronic coupling and of the Franck-Condon factor establish a useful predictive framework in biology, chemistry, and nanoscience. Describing the influence of geometric and energetic fluctuations on ET allows us to address a rich array of mechanistic and kinetic puzzles. How strongly is a protein's fold imprinted on the ET kinetics, and might thermal fluctuations "wash out" signatures of structure? What is the influence of thermal fluctuations on ET kinetics beyond averaging of the tunneling barrier structure? Do electronic coupling mechanisms change as donor and acceptor reposition in a protein, and what are the consequences for the ET kinetics? Do fluctuations access minority species that dominate tunneling? Can energy exchanges between the electron and bridge vibrations generate vibronic signatures that label some of the D-to-A pathways traversed by the electron, thus eliminating unmarked pathways that would otherwise contribute to the DA coupling (as in other "which way" or double-slit experiments)? Might medium fluctuations drive tunneling-hopping mechanistic transitions? How does the donor-state preparation, in particular, its polarization toward the acceptor and its momentum characteristics (which may introduce complex rather than pure real relationships among donor orbital amplitudes), influence the electronic dynamics? In this Account, we describe our recent studies that address puzzling questions of how conformational distributions, excited-state polarization, and electronic and nuclear dynamical effects influence ET in macromolecules. Indeed, conformational and dynamical effects arise in all transport regimes, including the tunneling, resonant transport, and hopping regimes. Importantly, these effects can induce switching among ET mechanisms.
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Affiliation(s)
- David N. Beratan
- Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708
| | | | - Ilya A. Balabin
- Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708
| | - Alexander Balaeff
- Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708
| | - Shahar Keinan
- Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708
| | - Ravindra Venkatramani
- Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708
| | - Dequan Xiao
- Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708
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Xiao D, Skourtis SS, Rubtsov IV, Beratan DN. Turning charge transfer on and off in a molecular interferometer with vibronic pathways. NANO LETTERS 2009; 9:1818-1823. [PMID: 19435376 DOI: 10.1021/nl8037695] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Inelastic electron-transfer kinetics in molecules with electron donor and acceptor units connected by a bridge is expected to be sensitive to bridge-localized vibronic interactions. Here, we show how inelastic electron transfer may be turned on and off in a double-slit style experiment that uses the molecule as an interferometer. We describe donor-acceptor interactions in terms of interfering vibronic coupling pathways that can be actively selected ("labeled") when pathway-specific vibrations are excited by infrared radiation. Thus, inelastic tunneling may be actively controlled, and we suggest strategies for building molecular scale quantum interferometers and switches based on this phenomenon.
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Affiliation(s)
- Dequan Xiao
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
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12
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Jiang J, Kula M, Luo Y. Molecular modeling of inelastic electron transport in molecular junctions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:374110. [PMID: 21694417 DOI: 10.1088/0953-8984/20/37/374110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A quantum chemical approach for the modeling of inelastic electron tunneling spectroscopy of molecular junctions based on scattering theory is presented. Within a harmonic approximation, the proposed method allows us to calculate the electron-vibration coupling strength analytically, which makes it applicable to many different systems. The calculated inelastic electron transport spectra are often in very good agreement with their experimental counterparts, allowing the revelation of detailed information about molecular conformations inside the junction, molecule-metal contact structures, and intermolecular interaction that is largely inaccessible experimentally.
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Affiliation(s)
- Jun Jiang
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden
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Okabayashi N, Konda Y, Komeda T. Inelastic electron tunneling spectroscopy of an alkanethiol self-assembled monolayer using scanning tunneling microscopy. PHYSICAL REVIEW LETTERS 2008; 100:217801. [PMID: 18518634 DOI: 10.1103/physrevlett.100.217801] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Indexed: 05/26/2023]
Abstract
We report inelastic electron tunneling spectroscopy (IETS) of a C8 alkanethiol self-assembled monolayer using a scanning tunneling microscope (STM). High-resolution STM IETS spectra show clear features of the C-H bending and C-C stretching modes in addition to the C-H stretching mode, which enables a precise comparison with previously reported vibrational spectroscopy, especially electron energy loss spectroscopy data. Intensity variation of vibrational peaks with tip position is discussed with the STM IETS detection mechanism.
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Affiliation(s)
- Norio Okabayashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, 980-0877, Japan
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Kahnt A, Guldi DM, de la Escosura A, Martínez-Díaz MV, Torres T. [2.2]Paracyclophane: a pseudoconjugated spacer for long-lived electron transfer in phthalocyanine–C60dyads. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b712751k] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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