中央研究院 原子與分子科學研究所
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許良彥 博士J. Phys. Chem. Lett. 14, 25, 5924–5931 (2023).To explore non-adiabatic effects caused by electromagnetic (EM) vacuum fluctuations in molecules, we develop a general theory of internal conversion (IC) in the framework of quantum electrodynamics and propose a new mechanism, “quantum electrodynamic internal conversion” (QED-IC). The theory allows us to compute the rates of the conventional IC and QED-IC processes at the first-principles level. Our simulations manifest that, under experimentally feasible weak light–matter coupling conditions, EM vacuum fluctuations can significantly affect IC rates by an order of magnitude. Moreover, our theory elucidates three key factors in the QED-IC mechanism: the effective mode volume, coupling-weighted normal mode alignment, and molecular rigidity. The theory successfully captures the nucleus–photon interaction in the factor “co ...
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余慈顏 博士Nature Communications, 13, 1513 (2022).Limited methods are available for investigating the reorientational dynamics of A-site cations in two-dimensional organic–inorganic hybrid perovskites (2D OIHPs), which play a pivotal role in determining their physical properties. Here, we describe an approach to study the dynamics of A-site cations using solid-state NMR and stable isotope labelling. 2H NMR of 2D OIHPs incorporating methyl-d3-ammonium cations (d3-MA) reveals the existence of multiple modes of reorientational motions of MA. Rotational-echo double resonance (REDOR) NMR of 2D OIHPs incorporating 15N- and 13C-labeled methylammonium cations (13C,15N-MA) reflects the averaged dipolar coupling between the C and N nuclei undergoing different modes of motions. Our study reveals the interplay between the A-si ...
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王偉華 博士Nano Lett., 22, 6, 2270–2276 (2022).Understanding the Coulomb interactions between two-dimensional (2D) materials and adjacent ions/impurities is essential to realizing 2D material-based hybrid devices. Electrostatic gating via ionic liquids (ILs) has been employed to study the properties of 2D materials. However, the intrinsic interactions between 2D materials and ILs are rarely addressed. This work studies the intersystem Coulomb interactions in IL-functionalized InSe field-effect transistors by displacement current measurements. We uncover a strong self-gating effect that yields a 50-fold enhancement in interfacial capacitance, reaching 550 nF/cm2 in the maximum. Moreover, we reveal the IL-phase-dependent transport characteristics, including the channel current, carrier mobility, and density, substantiating the self-gating at the InSe/IL interface. The dominance of self ...
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謝雅萍 博士Nano Lett., https://doi.org/10.1021/acs.nanolett.1c02331 (2021).We here demonstrate the multifunctional properties of atomically thin heterojunctions that are enabled by strong interfacial interactions and their integration into ultra-high performance, self-powered sensors. Epitaxial alignment between tin diselenide and graphene through direct growth produces thermoelectric and mechanoelectric properties beyond the ability of either component. An unprecedented ZT of 2.43 originated from the synergistic combination of graphene’s high carrier conductivity and SnSe2 mediated thermal conductivity lowering. Moreover, strong interaction at the SnSe2/graphene interface produces stress localization that results in a novel 2D-crack-assisted strain sensing mechanism whose sensitivity (GF=450) is superior to all other 2D materials. Finally, the graphene-assisted growth process, permits the formation of hi ...
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羅佩凌 博士Communications Chemistry, 6, 130 (2023)Ozonolysis of isoprene is considered to be an important source of formic acid (HCOOH), but its underlying reaction mechanisms related to HCOOH formation are poorly understood. Here, we report the kinetic and product studies of the reaction between the simplest Criegee intermediate (CH2OO) and formaldehyde (HCHO), both of which are the primary products formed in ozonolysis of isoprene. By utilizing time-resolved infrared laser spectrometry with the multifunctional dual-comb spectrometers, the rate coefficient kCH2OO+HCHO is determined to be (4.11 ± 0.25) × 10−12 cm3 molecule−1 s−1 at 296 K and a negative temperature dependence of the rate coefficient is observed and described by an Arrheni ...
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陳貴賢 博士Nano Energy, 93, 106809 (2022).Employing direct Z-scheme semiconductor heterostructures in photocatalysis offers efficient charge carrier separation and isolation of both redox reactions, thus beneficial to reduce CO2 into solar fuels. Here, a ZnS/ZnIn2S4 heterostructure, comprising cubic ZnS nanocrystals on hexagonal ZnIn2S4 (ZIS) nanosheets, is successfully fabricated in a single-pot hydrothermal approach. The composite ZnS/ZnIn2S4 exhibits microstrain at its interface with an electric field favorable for Z-scheme. At an optimum ratio of Zn:In (~ 1:0.5), an excellent photochemical quantum efficiency of around 0.8% is reached, nearly 200-fold boost compared with pristine ZnS. Electronic levels and band alignments are deduced from ultraviolet photoemission spectroscopy and UV-Vis. Evidence of the direct ...
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羅佩凌 博士Analytical Chemistry, 94, 5752 (2022).A novel spectrometer has been developed based on synchronized two-color time-resolved dual-comb spectroscopy (TRDCS), enabling high-resolution hyperspectral measurements. The proposed approach with TRDCS exhibits great potential in quantitative diagnostics of multispecies and opens opportunities to decipher key reaction mechanisms in atmospheric chemistry. In this work, we perform simultaneous measurements in two distinct molecular fingerprint regions near 2.9 and 7.8 μm by employing the new approach with synchronized two-color TRDCS. Upon flash photolysis of CH2I2/O2/N2 gas mixtures, multiple reaction species, involving the simplest Criegee intermediates (CH2OO), formaldehyde (CH2O), hydroxyl (OH) and hydroperoxy (HO2) radicals are simultaneously detected with mic ...
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許良彥 博士Journal of Physical Chemistry Letters, 13, 9695–9702 (2022).Richard Feynman stated that “The theory behind chemistry is quantum electrodynamics”. However, harnessing quantum-electrodynamic (QED) effects to modify chemical reactions is a grand challenge and currently has only been reported in experiments using cavities due to the limitation of strong light–matter coupling. In this article, we demonstrate that QED effects can significantly enhance the rate of electron transfer (ET) by several orders of magnitude in the absence of cavities, which is implicitly supported by experimental reports. To understand how cavity-free QED effects are involved in ET reactions, we incorporate the effect of infinite one-photon states into Marcus theory, derive an explicit expression for the rate of radiative ET, and develop the concept of “electron transfer overlap”. Moreover, QED effects may l ...
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任祥華 博士Nature Communications 13, 4598 (2022).Explorations of symmetry and topology have led to important breakthroughs in quantum optics, but much richer behaviors arise from the non-Hermitian nature of light-matter interactions. A high-reflectivity, non-Hermitian optical mirror can be realized by a two-dimensional subwavelength array of neutral atoms near the cooperative resonance associated with the collective dipole modes. Here we show that exceptional points develop from a nondefective degeneracy by lowering the crystal symmetry of a square atomic lattice, and dispersive bulk Fermi arcs that originate from exceptional points are truncated by the light cone. From its nontrivial energy spectra topology, we demonstrate that the geometry-dependent non-Hermitian skin effect emerges in a ribbon geometry. Furthermore, skin modes localized at a boundary show a scale-free behavior that stems from ...
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謝雅萍 博士Nature Communications, 12:6291 (2021).We here report on the direct observation of ferroelectric properties of water ice in its 2D phase. Upon nanoelectromechanical confinement between two graphene layers, water forms a 2D ice phase at room temperature that exhibits a strong and permanent dipole which depends on the previously applied field, representing clear evidence for ferroelectric ordering. Characterization of this permanent polarization with respect to varying water partial pressure and temperature reveals the importance of forming a monolayer of 2D ice for ferroelectric ordering which agrees with ab-initio and molecular dynamics simulations conducted. The observed robust ferroelectric properties of 2D ice enable novel nanoelectromechanical devices that exhibit memristive properties. A unique bipolar mechanical switching behavior is observed where previous charging history contro ...
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詹楊皓 博士Proceedings of National Academy of Sciences, 118 (25) e1906938118 (2021).Shift current is a direct current generated from nonlinear light–matter interaction in a noncentrosymmetric crystal and is considered a promising candidate for next-generation photovoltaic devices. The mechanism for shift currents in real materials is, however, still not well understood, especially if electron–hole interactions are included. Here, we employ a first-principles interacting Green’s-function approach on the Keldysh contour with real-time propagation to study photocurrents generated by nonlinear optical processes under continuous wave illumination in real materials. We demonstrate a strong direct current shift current at subbandgap excitation frequencies in monolayer GeS due to strongly bound excitons, as well as a giant excitonic enhancement in the shift current coefficients at above bandgap photon frequencies. Our re ...
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賴品光 博士Nature Protocols. doi: 10.1038/s41596-021-00564-8 (2021).The dynamics of DNA double-strand break (DSB) repairs including homology-directed repair and nonhomologous end joining play an important role in diseases and therapies. However, investigating DSB repair is typically a low-throughput and cross-sectional process, requiring disruption of cells and organisms for subsequent nuclease-, sequencing- or reporter-based assays. In this protocol, we provide instructions for establishing a bioluminescent repair reporter system using engineered Gaussia and Vargula luciferases for noninvasive tracking of homology-directed repair and nonhomologous end joining, respectively, induced by SceI meganuclease, SpCas9 or SpCas9 D10A nickase-mediated editing. We also describe complementation with orthogonal DSB repair assays and omics analyses to validate the reporter readouts. The bioluminescent repair reporter system pro ...
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謝佳龍 博士ACS Nano, 16(2): 2774-2788 (2022).Chromatin is a DNA–protein complex that is densely packed in the cell nucleus. The nanoscale chromatin compaction plays critical roles in the modulation of cell nuclear processes. However, little is known about the spatiotemporal dynamics of chromatin compaction states because it remains difficult to quantitatively measure the chromatin compaction level in live cells. Here, we demonstrate a strategy, referenced as DYNAMICS imaging, for mapping chromatin organization in live cell nuclei by analyzing the dynamic scattering signal of molecular fluctuations. Highly sensitive optical interference microscopy, coherent brightfield (COBRI) microscopy, is implemented to detect the linear scattering of unlabeled chromatin at a high speed. A theoretical model is established to determine the local chromatin density from the statistical fluctuation of the ...
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賴品光 博士Advanced Materials. https://doi.org/10.1002/adma.202208966 (2023).Our latest publication employed PalmGRET, a bioluminescence-resonance-energy-transfer (BRET)-based EV reporter, to discover an abundant release of big EVs (bEVs; >200 nm) by aggressive breast cancers when compared to epithelial and less malignant cells. bEVs have been largely overshadowed by small EVs (sEVs; <200 nm) in EV research in the past decades. This is the first study to accurately detect and systematically compare biophysical property and in vivo profiles of breast cancer bEVs and sEVs. This is followed by the identification of EV surface oncoproteins, and their role in modulating organotropism and tumorigenic potential of the bEVs and sEVs. Our landmark findings impart a broad and deep reference for upcoming EV studies, with an emphasis on EV engineering for diagnosis and therapeutic applications.
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2023-09-07
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2023-06-08
演講資訊
Oct
05
2023
05
2023
Liquid-Liquid Phase Separation of Biological Systems
Dr. Michael Rosen, Department of Biophysics, University of Texas Southwestern Medical Center, USA
2023-10-05 下午 03:30 台大化學系松柏講堂
Oct
12
2023
12
2023
Optical microscopy meets electron microscopy in 3D
陳壁彰副研究員, 本院應用科學研究中心
2023-10-12 下午 03:30 浦大邦紀念講堂
Oct
13
2023
13
2023
Ferroelectric topological superconductor
Prof. Feng Liu, Distinguished and Ivan B. Cutler Professor, Department of Materials Science and Engineering, University of Utah, USA
2023-10-13 上午 10:00 張昭鼎紀念講堂
Oct
19
2023
19
2023
Bridging in vitro. and in vivo. through mechanobiology
林耿慧副研究員, 本院物理研究所
2023-10-19 下午 03:30 浦大邦紀念講堂
Oct
26
2023
26
2023
How I advance to the cutting-edge research of chemical science: purely my experience and perspective
周必泰教授, 國立臺灣大學化學系
2023-10-26 下午 02:30 台大化學系松柏講堂
活動資訊
The 6th International Conference on Molecular Simulation (ICMS 2023)
國立臺灣大學博雅教學館
2023-10-06 上午 09:00 ~ 2023-10-09 下午 08:00
2023-10-06 上午 09:00 ~ 2023-10-09 下午 08:00
We are happy to announce that the 6th International Conference on Molecular Simulation (ICMS 2023) will be held from October 6th to 9th 2023 in the venues of the National Taiwan University, Taipei, Taiwan.
Molecular simulations have become an essential tool in Physics, Chemistry, Biological/Material Sciences, and Engineering over the last few decades. The International Conference on Molecular Simulations (ICMS) was initiated by the Molecular Simulation Society of Japan in 1994 to promote molecular simulations as a platform for inter-disciplinary research. The first three meetings were held in 1994, 2004, and 2013 in Fukui, Tsukuba, and Kobe, respectively. After the 4th and 5th ICMS in Shanghai 2016 and Jeju 2019 with hundreds of participants from more than 20 countries, the 6th ICMS was initially scheduled to take place in Taipei in 2022. However, the meeting has so far been hindered due to the global COVID-19 pandemic.
Now, with the world recovering from COVID-19 and Taiwan lifting its travel restrictions, we hope that the ICMS 2023 will not only provide a platform for scientists and engineers to meet in person again and to share state-of-the-art development in molecular simulations. We also hope it will facilitate international collaborations and promote scientific and technological advances through molecular simulations.
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最後更新於 2023-10-03 18:24:43
地址： 106319 台北市羅斯福路四段一號 或 106923 臺北臺大郵局 第23-166號信箱
電話：886-2-2362-0212 傳真：886-2-2362-0200 電子郵件：iamspublic@gate.sinica.edu.tw
最後更新於 2023-10-03 18:24:43
