A5064691163- Molecular Junctions and Nanostructures
- Surface Chemistry and Catalysis
- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Surface and Thin Film Phenomena
- Plasmonic and Surface Plasmon Research
- Gold and Silver Nanoparticles Synthesis and Applications
- Force Microscopy Techniques and Applications
- Intracranial Aneurysms: Treatment and Complications
- Quantum, superfluid, helium dynamics
- Near-Field Optical Microscopy
- Bone Tissue Engineering Materials
- Graphene research and applications
- Neurosurgical Procedures and Complications
- Quantum Dots Synthesis And Properties
- Vascular Malformations Diagnosis and Treatment
- Cerebrovascular and Carotid Artery Diseases
- Mechanical and Optical Resonators
- Synthetic Organic Chemistry Methods
- Photochemistry and Electron Transfer Studies
- Organometallic Complex Synthesis and Catalysis
- Monoclonal and Polyclonal Antibodies Research
- Glycosylation and Glycoproteins Research
- Nanowire Synthesis and Applications
- Spectroscopy and Laser Applications
Institute for Molecular Science
2020-2025
The Graduate University for Advanced Studies, SOKENDAI
2022-2025
Fritz Haber Institute of the Max Planck Society
2015-2024
National Institutes of Natural Sciences
2022-2024
Yamagata Prefectural Central Hospital
2003-2022
Japan Science and Technology Agency
2017-2020
Tohoku University
1976-2018
Faraday Technology (United States)
2018
Kyushu University
2018
Astellas Pharma (Japan)
2018
Octacalcium phosphate (OCP) has been advocated to be a precursor of biological apatite crystals in bones and teeth. Our previous studies showed that synthetic OCP stimulates bone regeneration, followed by the progressive conversion into hydroxyapatite (HA), when implanted defects. However, precise mechanism induce osteogenic phenotype osteoblasts not identified. The present study was designed investigate whether physicochemical aspect, specific derived from structural properties OCP,...
We address the double hydrogen transfer (DHT) dynamics of porphycene molecule: A complex paradigmatic system where making and breaking H-bonds in a highly anharmonic potential energy surface requires quantum mechanical treatment not only electrons, but also nuclei. combine density-functional theory calculations, employing hybrid functionals van der Waals corrections, with recently proposed optimized path-integral ring-polymer methods for approximation vibrational spectra reaction rates. Our...
The dynamics of water dimers was investigated at the single-molecule level by using a scanning tunneling microscope. two molecules in dimer, bound on Cu(110) surface 6 K, were observed to exchange their roles as hydrogen-bond donor and acceptor via rearrangement. interchange rate is approximately 60 times higher for (H2O)2 than (D2O)2, suggesting that quantum involved process. enhanced upon excitation intermolecular mode correlates with reaction coordinate.
We report the direct observation of intramolecular hydrogen atom transfer reactions (tautomerization) within a single porphycene molecule on Cu(110) surface by scanning tunneling microscopy. It is found that tautomerization can be induced via inelastic electron at 5 K. By measuring bias-dependent rate isotope-substituted molecules, we assign microscopy-induced to excitation specific molecular vibrations. Furthermore, these vibrations appear as characteristic features in $dI/dV$ spectra...
The formation of extended two-dimensional metal-organic coordination networks (2D-MOCNs) showing high adaptability to surface step edges and structural defects is revealed by scanning tunneling microscopy. Rod-like 4,4'-di-(1,4-buta-1,3-diynyl)-benzoic acid (BDBA) iron atoms assemble into 2D-MOCNs on Au(111) Ag(100) surfaces. Independent from the chosen substrate its symmetry MOCN grows continuously over multiple terraces through mutual in-phase structure adaptation network domains at as...
Molecular machines are a key component in the vision of molecular nanotechnology and have potential to transport species cargo on surfaces. The motion such should be triggered remotely, ultimately allowing large number molecules propelled by single source, with light being an attractive stimulus. Here, we report upon photoinduced translation across surface characterizing before after illumination. Illumination containing motor unit results enhancement diffusion molecules. effect vanishes if...
Here, we report the study of tautomerization within a single porphycene molecule adsorbed on Cu(111) surface using low-temperature scanning tunneling microscopy (STM) at 5 K. While molecules are exclusively in thermodynamically stable trans tautomer after deposition, voltage pulse from STM can induce unidirectional → cis and reversible ↔ tautomerization. From current dependence yield (rate), it is revealed that process induced by vibrational excitation via inelastic electron tunneling....
Molecular switches are of fundamental importance in nature, and light is an important stimulus to selectively drive the switching process. However, local dynamics a conformational change these molecules remain far from being completely understood at single-molecule level. Here, we report direct observation photoinduced tautomerization single porphycene on Cu(111) surface by using combination low-temperature scanning tunneling microscopy laser excitation near-infrared ultraviolet regime. It...
Charge-transfer enhancement of Raman scattering plays a crucial role in current-carrying molecular junctions. However, the microscopic mechanism light such nonequilibrium systems is still imperfectly understood. Here, using low-temperature tip-enhanced spectroscopy (TERS), we investigate how evolves as function gap distance single C60-molecule junction consisting an Ag tip and various metal surfaces. Precise gap-distance control allows examination two distinct transport regimes, namely...
Tip-enhanced vibrational spectroscopy has advanced to routinely attain nanoscale spatial resolution, with tip-enhanced Raman even achieving atomic-scale and submolecular sensitivity. infrared techniques, such as nano-FTIR AFM-IR spectroscopy, have also enabled the chemical analysis of molecular monolayers, inorganic nanoparticles, protein complexes. However, fundamental limits nanospectroscopy in terms resolution sensitivity remained elusive, calling for a quantitative understanding...
We report tip-enhanced Raman spectroscopy of graphene nanoribbons (GNRs) fabricated on Au(111) by the on-surface polymerization technique under ultrahigh-vacuum conditions. The 0.74 nm wide armchair GNRs are directly observed scanning tunneling microscopy at room temperature, and characteristic vibration modes appear in both far- near-field (tip-enhanced) spectra. scattering is enhanced up to 4 × 105 near-field, while a strong intensity fluctuation (blinking) frequently emerges time series...
The evaluation of subvisible particles, including protein aggregates, in therapeutic products has been great interest for both pharmaceutical manufacturers and regulatory agencies. To date, the flow imaging (FI) method emerged as a powerful tool instead light obscuration (LO) due to fact that (1) aggregates contain highly transparent particles thereby escape detection by LO (2) FI provides detailed morphological characteristics particles. However, not yet standardized nor listed any...
Low-temperature tip-enhanced Raman spectroscopy (TERS) enables chemical identification with single-molecule sensitivity and extremely high spatial resolution even down to the atomic scale. The large enhancement of scattering obtained in TERS can originate from physical and/or mechanisms. Whereas requires a strong near-field through excitation localized surface plasmons, is governed by resonance electronic structure sample, which also known as spectroscopy. Here we report on (TERRS) ultrathin...
Quantum tunneling of hydrogen atoms (or protons) plays a crucial role in many chemical and biological reactions. Although single particle has been examined extensively various one-dimensional potentials, many-particle high-dimensional potential energy surfaces remains poorly understood. Here we present direct observation double atom transfer (tautomerization) within porphycene molecule on Ag(110) surface using cryogenic scanning microscope (STM). The tautomerization rates are temperature...
Tip-enhanced Raman scattering (TERS) in ångström-scale plasmonic cavities has drawn increasing attention. However, at vanishing cavity distances remains unexplored. Here, we show the evolution of TERS transition from tunneling regime to atomic point contact (APC). A stable APC is reversibly formed junction between an Ag tip and ultrathin ZnO or NaCl films on Ag(111) surface 10 K. An abrupt increase intensity occurs upon formation for ZnO, but not NaCl. This remarkable observation...
Dynamics of a hydroxyl (OH) group and its dimer adsorbed on Cu(110) is investigated at 6 K with scanning tunneling microscope (STM). For the monomer, inclined OH axis switches back forth between two equivalent orientations via hydrogen-atom tunneling. The motion enhanced by electron that excites bending mode directly correlates reaction coordinate. inelastic electron-tunneling spectra exhibit either peak or dip, depending position STM tip over molecule. switch quenched for since it...
Near-field manipulation in plasmonic nanocavities can provide various applications nanoscale science and technology. In particular, a gap plasmon scanning tunneling microscope (STM) junction is of key interest to imaging spectroscopy. Here we show that spectral features STM be manipulated by nanofabrication Au tips using focused ion beam. An exemplary Fabry–Pérot type resonator surface plasmons demonstrated producing the tip with single groove on its shaft. Scanning luminescence spectra...
Tip-enhanced Raman scattering (TERS) has recently demonstrated the exceptional sensitivity to observe vibrational structures on atomic scale. However, it strongly relies electromagnetic enhancement in plasmonic nanogaps. Here, we demonstrate that point contact (APC) formation between a tip and surface of bulk Si sample can lead dramatic consequently phonons reconstructed Si(111)-7 × 7 be detected. Furthermore, chemical APC-TERS by probing local vibrations resulting from Si–O bonds partially...
Coherent phonon spectroscopy can provide microscopic insight into ultrafast lattice dynamics and its coupling to other degrees of freedom under nonequilibrium conditions. Ultrafast optical is a well-established method study coherent phonons, but the diffraction limit has hampered observing their local directly. Here, we demonstrate nanoscale using laser–induced scanning tunneling microscopy in plasmonic junction. phonons are locally excited ultrathin zinc oxide films by tightly confined...
Electromagnetic fields can be confined in the presence of metal nanostructures. Recently, subnanometer scale confinement has been demonstrated to occur at atomic protrusions on plasmonic Such an extreme field may dominate atomic-scale light-matter interactions "picocavities". However, it remains elucidated how atomic-level structures and electron transport affect properties a picocavity. Here, using low-temperature optical scanning tunneling microscopy (STM), we investigate inelastic light...
Abstract Atomic-scale control of photochemistry facilitates extreme miniaturisation optoelectronic devices. Localised surface plasmons, which provide strong confinement and enhancement electromagnetic fields at the nanoscale, secure a route to achieve sub-nanoscale reaction control. Such local plasmon-induced has been realised only in metallic structures so far. Here we demonstrate controlled single-molecule switching peryleneanhydride on silicon surface. Using plasmon-resonant tip...