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  • The Right Answer for the Right Reason: My Personal Goal for Quantum Chemistry
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Ernest R. Davidson

    A brief history of quantum theory is given to illustrate the barriers to progress caused by preconceived ideas. The biases in my own thinking which I had to overcome to approach the right answer for the right reason are discussed. This is followed by a personal autobiography illustrating how I have led a life of serendipity with no real sense of purpose. Chance events have shaped my life. The algorithms for which I am best known are briefly discussed. Then highlights from the many applications of theory to excited states, bonding in ice, spin properties and magnetism, (e,2e) shake-up spectra, and organic reactions are mentioned. This wide range of applications is mostly due to accidental collaboration with colleagues who sought my help. My real interest was in developing methods which could address these problems.

    更新日期:2019-11-18
  • Conical Intersections at the Nanoscale: Molecular Ideas for Materials
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Benjamin G. Levine, Michael P. Esch, B. Scott Fales, Dylan T. Hardwick, Wei-Tao Peng, Yinan Shu

    The ability to predict and describe nonradiative processes in molecules via the identification and characterization of conical intersections is one of the greatest recent successes of theoretical chemistry. Only recently, however, has this concept been extended to materials science, where nonradiative recombination limits the efficiencies of materials for various optoelectronic applications. In this review, we present recent advances in the theoretical study of conical intersections in semiconductor nanomaterials. After briefly introducing conical intersections, we argue that specific defects in materials can induce conical intersections between the ground and first excited electronic states, thus introducing pathways for nonradiative recombination. We present recent developments in theoretical methods, computational tools, and chemical intuition for the prediction of such defect-induced conical intersections. Through examples in various nanomaterials, we illustrate the significance of conical intersections for nanoscience. We also discuss challenges facing research in this area and opportunities for progress.

    更新日期:2019-11-18
  • Atmospheric Spectroscopy and Photochemistry at Environmental Water Interfaces
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    J. Zhong, M. Kumar, J.M. Anglada, M.T.C. Martins-Costa, M.F. Ruiz-Lopez, X.C. Zeng, Joseph S. Francisco

    The air–water interface is ubiquitous in nature, as manifested in the form of the surfaces of oceans, lakes, and atmospheric aerosols. The aerosol interface, in particular, can play a crucial role in atmospheric chemistry. The adsorption of atmospheric species onto and into aerosols modifies their concentrations and chemistries. Moreover, the aerosol phase allows otherwise unlikely solution-phase chemistry to occur in the atmosphere. The effect of the air–water interface on these processes is not entirely known. This review summarizes recent theoretical investigations of the interactions of atmosphere species with the air–water interface, including reactant adsorption, photochemistry, and the spectroscopy of reactants at the water surface, with an emphasis on understanding differences between interfacial chemistries and the chemistries in both bulk solution and the gas phase. The results discussed here enable an understanding of fundamental concepts that lead to potential air–water interface effects, providing a framework to understand the effects of water surfaces on our atmosphere.

    更新日期:2019-11-18
  • Why Are DNA and Protein Electron Transfer So Different?
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    David N. Beratan

    The corpus of electron transfer (ET) theory provides considerable power to describe the kinetics and dynamics of electron flow at the nanoscale. How is it, then, that nucleic acid (NA) ET continues to surprise, while protein-mediated ET is relatively free of mechanistic bombshells? I suggest that this difference originates in the distinct electronic energy landscapes for the two classes of reactions. In proteins, the donor/acceptor-to-bridge energy gap is typically several-fold larger than in NAs. NA ET can access tunneling, hopping, and resonant transport among the bases, and fluctuations can enable switching among mechanisms; protein ET is restricted to tunneling among redox active cofactors and, under strongly oxidizing conditions, a few privileged amino acid side chains. This review aims to provide conceptual unity to DNA and protein ET reaction mechanisms. The establishment of a unified mechanistic framework enabled the successful design of NA experiments that switch electronic coherence effects on and off for ET processes on a length scale of multiple nanometers and promises to provide inroads to directing and detecting charge flow in soft-wet matter.

    更新日期:2019-11-18
  • Photochemistry of Organic Retinal Prostheses
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Giovanni Manfredi, Elisabetta Colombo, Jonathan Barsotti, Fabio Benfenati, Guglielmo Lanzani

    Organic devices are attracting considerable attention as prostheses for the recovery of retinal light sensitivity lost to retinal degenerative disease. The biotic/abiotic interface created when light-sensitive polymers and living tissues are placed in contact allows excitation of a response in blind laboratory rats exposed to visual stimuli. Although polymer retinal prostheses have proved to be efficient, their working mechanism is far from being fully understood. In this review article, we discuss the results of the studies conducted on these kinds of polymer devices and compare them with the data found in the literature for inorganic retinal prostheses, where the working mechanisms are better comprehended. This comparison, which tries to set some reference values and figures of merit, is intended for use as a starting point to determine the direction for further investigation.

    更新日期:2019-11-18
  • Single Photon Sources in Atomically Thin Materials
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Milos Toth, Igor Aharonovich

    Layered materials are very attractive for studies of light–matter interactions at the nanoscale. In particular, isolated quantum systems such as color centers and quantum dots embedded in these materials are gaining interest due to their potential use in a variety of quantum technologies and nanophotonics. Here, we review the field of nonclassical light emission from van der Waals crystals and atomically thin two-dimensional materials. We focus on transition metal dichalcogenides and hexagonal boron nitride and discuss the fabrication and properties of quantum emitters in these systems and proof-of-concept experiments that provide a foundation for their integration in on-chip nanophotonic circuits. These experiments include tuning of the emission wavelength, electrical excitation, and coupling of the emitters to waveguides, dielectric cavities, and plasmonic resonators. Finally, we discuss current challenges in the field and provide an outlook to further stimulate scientific discussion.

    更新日期:2019-11-18
  • Kinetics of Drug Binding and Residence Time
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Mattia Bernetti, Matteo Masetti, Walter Rocchia, Andrea Cavalli

    The kinetics of drug binding and unbinding is assuming an increasingly crucial role in the long, costly process of bringing a new medicine to patients. For example, the time a drug spends in contact with its biological target is known as residence time (the inverse of the kinetic constant of the drug-target unbinding, 1/koff). Recent reports suggest that residence time could predict drug efficacy in vivo, perhaps even more effectively than conventional thermodynamic parameters (free energy, enthalpy, entropy). There are many experimental and computational methods for predicting drug-target residence time at an early stage of drug discovery programs. Here, we review and discuss the methodological approaches to estimating drug binding kinetics and residence time. We first introduce the theoretical background of drug binding kinetics from a physicochemical standpoint. We then analyze the recent literature in the field, starting from the experimental methodologies and applications thereof and moving to theoretical and computational approaches to the kinetics of drug binding and unbinding. We acknowledge the central role of molecular dynamics and related methods, which comprise a great number of the computational methods and applications reviewed here. However, we also consider kinetic Monte Carlo. We conclude with the outlook that drug (un)binding kinetics may soon become a go/no go step in the discovery and development of new medicines.

    更新日期:2019-11-18
  • Imaging Quantum Vortices in Superfluid Helium Droplets
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Oliver Gessner, Andrey F. Vilesov

    Free superfluid helium droplets constitute a versatile medium for a diverse range of experiments in physics and chemistry that extend from studies of the fundamental laws of superfluid motion to the synthesis of novel nanomaterials. In particular, the emergence of quantum vortices in rotating helium droplets is one of the most dramatic hallmarks of superfluidity and gives detailed access to the wave function describing the quantum liquid. This review provides an introduction to quantum vorticity in helium droplets, followed by a historical account of experiments on vortex visualization in bulk superfluid helium and a more detailed discussion of recent advances in the study of the rotational motion of isolated, nano- to micrometer-scale superfluid helium droplets. Ultrafast X-ray and extreme ultraviolet scattering techniques enabled by X-ray free-electron lasers and high-order harmonic generation in particular have facilitated the in situ detection of droplet shapes and the imaging of vortex structures inside individual, isolated droplets. New applications of helium droplets ranging from studies of quantum phase separations to mechanisms of low-temperature aggregation are discussed.

    更新日期:2019-11-18
  • Microscopy and Cell Biology: New Methods and New Questions
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Joshua D. Morris, Christine K. Payne

    Understanding the cellular basis of human health and disease requires the spatial resolution of microscopy and the molecular-level details provided by spectroscopy. This review highlights imaging methods at the intersection of microscopy and spectroscopy with applications in cell biology. Imaging methods are divided into three broad categories: fluorescence microscopy, label-free approaches, and imaging tools that can be applied to multiple imaging modalities. Just as these imaging methods allow researchers to address new biological questions, progress in biological sciences will drive the development of new imaging methods. We highlight four topics in cell biology that illustrate the need for new imaging tools: nanoparticle-cell interactions, intracellular redox chemistry, neuroscience, and the increasing use of spheroids and organoids. Overall, our goal is to provide a brief overview of individual imaging methods and highlight recent advances in the use of microscopy for cell biology.

    更新日期:2019-11-18
  • Ultrafast Dynamic Microscopy of Carrier and Exciton Transport
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Tong Zhu, Jordan M. Snaider, Long Yuan, Libai Huang

    We highlight the recent progress in ultrafast dynamic microscopy that combines ultrafast optical spectroscopy with microscopy approaches, focusing on the application transient absorption microscopy (TAM) to directly image energy and charge transport in solar energy harvesting and conversion systems. We discuss the principles, instrumentation, and resolutions of TAM. The simultaneous spatial, temporal, and excited-state-specific resolutions of TAM unraveled exciton and charge transport mechanisms that were previously obscured in conventional ultrafast spectroscopy measurements for systems such as organic solar cells, hybrid perovskite thin films, and molecular aggregates. We also discuss future directions to improve resolutions and to develop other ultrafast imaging contrasts beyond transient absorption.

    更新日期:2019-11-18
  • Multireference Theories of Electron Correlation Based on the Driven Similarity Renormalization Group
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Chenyang Li, Francesco A. Evangelista

    The driven similarity renormalization group (DSRG) provides an alternative way to address the intruder state problem in quantum chemistry. In this review, we discuss recent developments of multireference methods based on the DSRG. We provide a pedagogical introduction to the DSRG and its various extensions and discuss its formal properties in great detail. In addition, we report several illustrative applications of the DSRG to molecular systems.

    更新日期:2019-11-18
  • Chiral Plasmonic Nanostructures Enabled by Bottom-Up Approaches
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Maximilian J. Urban, Chenqi Shen, Xiang-Tian Kong, Chenggan Zhu, Alexander O. Govorov, Qiangbin Wang, Mario Hentschel, Na Liu

    We present a comprehensive review of recent developments in the field of chiral plasmonics. Significant advances have been made recently in understanding the working principles of chiral plasmonic structures. With advances in micro- and nanofabrication techniques, a variety of chiral plasmonic nanostructures have been experimentally realized; these tailored chiroptical properties vastly outperform those of their molecular counterparts. We focus on chiral plasmonic nanostructures created using bottom-up approaches, which not only allow for rational design and fabrication but most intriguingly in many cases also enable dynamic manipulation and tuning of chiroptical responses. We first discuss plasmon-induced chirality, resulting from the interaction of chiral molecules with plasmonic excitations. Subsequently, we discuss intrinsically chiral colloids, which give rise to optical chirality owing to their chiral shapes. Finally, we discuss plasmonic chirality, achieved by arranging achiral plasmonic particles into handed configurations on static or active templates. Chiral plasmonic nanostructures are very promising candidates for real-life applications owing to their significantly larger optical chirality than natural molecules. In addition, chiral plasmonic nanostructures offer engineerable and dynamic chiroptical responses, which are formidable to achieve in molecular systems. We thus anticipate that the field of chiral plasmonics will attract further widespread attention in applications ranging from enantioselective analysis to chiral sensing, structural determination, and in situ ultrasensitive detection of multiple disease biomarkers, as well as optical monitoring of transmembrane transport and intracellular metabolism.

    更新日期:2019-11-18
  • Interferometric Scattering Microscopy
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Gavin Young, Philipp Kukura

    Interferometric scattering microscopy (iSCAT) is an extremely sensitive imaging method based on the efficient detection of light scattered by nanoscopic objects. The ability to, at least in principle, maintain high imaging contrast independent of the exposure time or the scattering cross section of the object allows for unique applications in single-particle tracking, label-free imaging of nanoscopic (dis)assembly, and quantitative single-molecule characterization. We illustrate these capabilities in areas as diverse as mechanistic studies of motor protein function, viral capsid assembly, and single-molecule mass measurement in solution. We anticipate that iSCAT will become a widely used approach to unravel previously hidden details of biomolecular dynamics and interactions.

    更新日期:2019-11-18
  • Triplet-Pair States in Organic Semiconductors
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Andrew J. Musser, Jenny Clark

    Entanglement of states is one of the most surprising and counterintuitive consequences of quantum mechanics, with potent applications in cryptography and computing. In organic semiconductor materials, one particularly significant manifestation is the spin-entangled triplet-pair state, which consists of a pair of localized triplet excitons coupled into an overall spin-0, -1, or -2 configuration. The most widely analyzed of these is the spin-0 pair, denoted 1(TT), which was initially invoked in the 1960s to explain delayed fluorescence in acene films. It is considered an essential gateway state for triplet-triplet annihilation and the reverse process, singlet fission, enabling interconversion between one singlet and two triplet excitons without any change in overall spin. This state has returned to the forefront of organic materials research in recent years, thanks both to its central role in the resurgent field of singlet fission and to its implication in a host of exotic new photophysical behaviors. Here we review the properties of triplet-pair states, from first principles to recent experimental results.

    更新日期:2019-11-18
  • Optical and Physical Probing of Thermal Processes in Semiconductor and Plasmonic Nanocrystals
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-06-07
    Benjamin T. Diroll, Matthew S. Kirschner, Peijun Guo, Richard D. Schaller

    This article reviews thermal properties of semiconductor and emergent plasmonic nanomaterials, focusing on mechanisms through which hot carriers and phonons are produced and dissipated as well as the related impacts on optoelectronic properties. Elevated equilibrium temperatures, of particular relevance for implementation of nanomaterials in devices, affect absorptive and radiative transitions as well as emission efficiency that can present reversible and irreversible changes with temperature. In noble metal or doped semiconductor/insulator nanomaterials, hot carriers and lattice heating can substantially influence localized surface plasmon resonances and yield large ultrafast changes in transmission or strongly oscillatory coherences. Transient optical and diffraction characterizations enable nonequilibrium investigations of phonon dynamics and cooling such as lattice expansion and crystal phase stability. Timescales of nanoparticle thermalization with surroundings and transport of heat within films of such materials are also discussed.

    更新日期:2019-11-18
  • Spatially Resolved Exciton and Charge Transport in Emerging Semiconductors.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2019-11-23
    Naomi S Ginsberg,William A Tisdale

    We review recent advances in the characterization of electronic forms of energy transport in emerging semiconductors. The approaches described all temporally and spatially resolve the evolution of initially localized populations of photogenerated excitons or charge carriers. We first provide a comprehensive background for describing the physical origin and nature of electronic energy transport both microscopically and from the perspective of the observer. We introduce the new family of far-field, time-resolved optical microscopies developed to directly resolve not only the extent of this transport but also its potentially temporally and spatially dependent rate. We review a representation of examples from the recent literature, including investigation of energy flow in colloidal quantum dot solids, organic semiconductors, organic-inorganic metal halide perovskites, and 2D transition metal dichalcogenides. These examples illustrate how traditional parameters like diffusivity are applicable only within limited spatiotemporal ranges and how the techniques at the core of this review, especially when taken together, are revealing a more complete picture of the spatiotemporal evolution of energy transport in complex semiconductors, even as a function of their structural heterogeneities. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 71 is April 20, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

    更新日期:2019-11-01
  • Physical chemistry. Preface.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2008-05-28

    更新日期:2019-11-01
  • Physical chemistry. Preface.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2009-05-19

    更新日期:2019-11-01
  • Liquid Cell Transmission Electron Microscopy.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-05-25
    Hong-Gang Liao,Haimei Zheng

    Liquid cell transmission electron microscopy (TEM) has attracted significant interest in recent years. With nanofabricated liquid cells, it has been possible to image through liquids using TEM with subnanometer resolution, and many previously unseen materials dynamics have been revealed. Liquid cell TEM has been applied to many areas of research, ranging from chemistry to physics, materials science, and biology. So far, topics of study include nanoparticle growth and assembly, electrochemical deposition and lithiation for batteries, tracking and manipulation of nanoparticles, catalysis, and imaging of biological materials. In this article, we first review the development of liquid cell TEM and then highlight progress in various areas of research. In the study of nanoparticle growth, the electron beam can serve both as the illumination source for imaging and as the input energy for reactions. However, many other research topics require the control of electron beam effects to minimize electron beam damage. We discuss efforts to understand electron beam-liquid matter interactions. Finally, we provide a perspective on future challenges and opportunities in liquid cell TEM.

    更新日期:2019-11-01
  • Water-Mediated Hydrophobic Interactions.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-05-25
    Dor Ben-Amotz

    Hydrophobic interactions are driven by the combined influence of the direct attraction between oily solutes and an additional water-mediated interaction whose magnitude (and sign) depends sensitively on both solute size and attraction. The resulting delicate balance can lead to a slightly repulsive water-mediated interaction that drives oily molecules apart rather than pushing them together and thus opposes their direct (van der Waals) attraction for each other. As a consequence, competing solute size-dependent crossovers weaken hydrophobic interactions sufficiently that they are only expected to significantly exceed random thermal energy fluctuations for processes that bury more than ∼1 nm(2) of water-exposed area.

    更新日期:2019-11-01
  • Measuring the Hydrodynamic Size of Nanoparticles Using Fluctuation Correlation Spectroscopy.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-05-25
    Sergio Dominguez-Medina,Sishan Chen,Jan Blankenburg,Pattanawit Swanglap,Christy F Landes,Stephan Link

    Fluctuation correlation spectroscopy (FCS) is a well-established analytical technique traditionally used to monitor molecular diffusion in dilute solutions, the dynamics of chemical reactions, and molecular processes inside living cells. In this review, we present the recent use of FCS for measuring the size of colloidal nanoparticles in solution. We review the theoretical basis and experimental implementation of this technique and its advantages and limitations. In particular, we show examples of the use of FCS to measure the size of gold nanoparticles, monitor the rotational dynamics of gold nanorods, and investigate the formation of protein coronas on nanoparticles.

    更新日期:2019-11-01
  • Biophysical Insights from Temperature-Dependent Single-Molecule Förster Resonance Energy Transfer.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-05-25
    Erik D Holmstrom,David J Nesbitt

    Single-molecule fluorescence microscopy techniques can be used in combination with micrometer length-scale temperature control and Förster resonance energy transfer (FRET) in order to gain detailed information about fundamental biophysical phenomena. In particular, this combination of techniques has helped foster the development of remarkable quantitative tools for studying both time- and temperature-dependent structural kinetics of biopolymers. Over the past decade, multiple research efforts have successfully incorporated precise spatial and temporal control of temperature into single-molecule FRET (smFRET)-based experiments, which have uncovered critical thermodynamic information on a wide range of biological systems such as conformational dynamics of nucleic acids. This review provides an overview of various temperature-dependent smFRET approaches from our laboratory and others, highlighting efforts in which such methods have been successfully applied to studies of single-molecule nucleic acid folding.

    更新日期:2019-11-01
  • Molecular Shape and the Hydrophobic Effect.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-05-25
    Matthew B Hillyer,Bruce C Gibb

    This review focuses on papers published since 2000 on the topic of the properties of solutes in water. More specifically, it evaluates the state of the art of our understanding of the complex relationship between the shape of a hydrophobe and the hydrophobic effect. To highlight this, we present a selection of references covering both empirical and molecular dynamics studies of small (molecular-scale) solutes. These include empirical studies of small molecules, synthetic hosts, crystalline monolayers, and proteins, as well as in silico investigations of entities such as idealized hard and soft spheres, small solutes, hydrophobic plates, artificial concavity, molecular hosts, carbon nanotubes and spheres, and proteins.

    更新日期:2019-11-01
  • Understanding the Surface Hopping View of Electronic Transitions and Decoherence.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-05-25
    Joseph E Subotnik,Amber Jain,Brian Landry,Andrew Petit,Wenjun Ouyang,Nicole Bellonzi

    We present a current, up-to-date review of the surface hopping methodology for solving nonadiabatic problems, 25 years after Tully published the fewest switches surface hopping algorithm. After reviewing the original motivation for and failures of the algorithm, we give a detailed examination of modern advances, focusing on both theoretical and practical issues. We highlight how one can partially derive surface hopping from the Schrödinger equation in the adiabatic basis, how one can change basis within the surface hopping algorithm, and how one should understand and apply the notions of decoherence and wavepacket bifurcation. The question of time reversibility and detailed balance is also examined at length. Recent applications to photoexcited conjugated polymers are discussed briefly.

    更新日期:2019-11-01
  • Characterizing Localized Surface Plasmons Using Electron Energy-Loss Spectroscopy.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-05-25
    Charles Cherqui,Niket Thakkar,Guoliang Li,Jon P Camden,David J Masiello

    Electron energy-loss spectroscopy (EELS) offers a window to view nanoscale properties and processes. When performed in a scanning transmission electron microscope, EELS can simultaneously render images of nanoscale objects with subnanometer spatial resolution and correlate them with spectroscopic information at a spectral resolution of ∼10-100 meV. Consequently, EELS is a near-perfect tool for understanding the optical and electronic properties of individual plasmonic metal nanoparticles and few-nanoparticle assemblies, which are significant in a wide range of fields. This review presents an overview of basic plasmonics and EELS theory and highlights several recent noteworthy experiments involving the interrogation of plasmonic metal nanoparticle systems using electron beams.

    更新日期:2019-11-01
  • Charge Transfer Dynamics from Photoexcited Semiconductor Quantum Dots.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-05-25
    Haiming Zhu,Ye Yang,Kaifeng Wu,Tianquan Lian

    Understanding photoinduced charge transfer from nanomaterials is essential to the many applications of these materials. This review summarizes recent progress in understanding charge transfer from quantum dots (QDs), an ideal model system for investigating fundamental charge transfer properties of low-dimensional quantum-confined nanomaterials. We first discuss charge transfer from QDs to weakly coupled acceptors within the framework of Marcus nonadiabatic electron transfer (ET) theory, focusing on the dependence of ET rates on reorganization energy, electronic coupling, and driving force. Because of the strong electron-hole interaction, we show that ET from QDs should be described by the Auger-assisted ET model, which is significantly different from ET between molecules or from bulk semiconductor electrodes. For strongly quantum-confined QDs on semiconductor surfaces, the coupling can fall within the strong coupling limit, in which case the donor-acceptor interaction and ET properties can be described by the Newns-Anderson model of chemisorption. We also briefly discuss recent progress in controlling charge transfer properties in quantum-confined nanoheterostructures through wavefunction engineering and multiple exciton dissociation. Finally, we identify a few key areas for further research.

    更新日期:2019-11-01
  • Vibrational Heat Transport in Molecular Junctions.
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-05-25
    Dvira Segal,Bijay Kumar Agarwalla

    We review studies of vibrational energy transfer in a molecular junction geometry, consisting of a molecule bridging two heat reservoirs, solids or large chemical compounds. This setup is of interest for applications in molecular electronics, thermoelectrics, and nanophononics, and for addressing basic questions in the theory of classical and quantum transport. Calculations show that system size, disorder, structure, dimensionality, internal anharmonicities, contact interaction, and quantum coherent effects are factors that combine to determine the predominant mechanism (ballistic/diffusive), effectiveness (poor/good), and functionality (linear/nonlinear) of thermal conduction at the nanoscale. We review recent experiments and relevant calculations of quantum heat transfer in molecular junctions. We recount the Landauer approach, appropriate for the study of elastic (harmonic) phononic transport, and outline techniques that incorporate molecular anharmonicities. Theoretical methods are described along with examples illustrating the challenge of reaching control over vibrational heat conduction in molecules.

    更新日期:2019-11-01
  • Addressing the Challenge of Molecular Change: An Interim Report
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Raphael D. Levine

    Invited by the editorial committee of the Annual Review of Physical Chemistry to “contribute my autobiography,” I present it here, as I understand the term. It is about my parents, my mentors, my coworkers, and my friends in learning and the scientific problems that we tried to address. Courtesy of the editorial assistance of Annual Reviews, some of the science is in the figure captions and sidebars. I am by no means done: I am currently trying to fuse the quantitative rigor of physical chemistry with systems biology while also dealing with a post–Born-Oppenheimer regime in electronic dynamics and am attempting to instruct molecules to perform advanced logic.

    更新日期:2019-02-26
  • Biomimetic Structural Materials: Inspiration from Design and Assembly
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Nicholas A. Yaraghi, David Kisailus

    Nature assembles weak organic and inorganic constituents into sophisticated hierarchical structures, forming structural composites that demonstrate impressive combinations of strength and toughness. Two such composites are the nacre structure forming the inner layer of many mollusk shells, whose brick-and-mortar architecture has been the gold standard for biomimetic composites, and the cuticle forming the arthropod exoskeleton, whose helicoidal fiber-reinforced architecture has only recently attracted interest for structural biomimetics. In this review, we detail recent biomimetic efforts for the fabrication of strong and tough composite materials possessing the brick-and-mortar and helicoidal architectures. Techniques discussed for the fabrication of nacre- and cuticle-mimetic structures include freeze casting, layer-by-layer deposition, spray deposition, magnetically assisted slip casting, fiber-reinforced composite processing, additive manufacturing, and cholesteric self-assembly. Advantages and limitations to these processes are discussed, as well as the future outlook on the biomimetic landscape for structural composite materials.

    更新日期:2019-02-26
  • An Active Approach to Colloidal Self-Assembly
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Stewart A. Mallory, Chantal Valeriani, Angelo Cacciuto

    In this review, we discuss recent advances in the self-assembly of self-propelled colloidal particles and highlight some of the most exciting results in this field, with a specific focus on dry active matter. We explore this phenomenology through the lens of the complexity of the colloidal building blocks. We begin by considering the behavior of isotropic spherical particles. We then discuss the case of amphiphilic and dipolar Janus particles. Finally, we show how the geometry of the colloids and/or the directionality of their interactions can be used to control the physical properties of the assembled active aggregates, and we suggest possible strategies for how to exploit activity as a tunable driving force for self-assembly. The unique properties of active colloids lend promise to the design of the next generation of functional, environment-sensing microstructures able to perform specific tasks in an autonomous and targeted manner.

    更新日期:2019-02-26
  • Excitons in Single-Walled Carbon Nanotubes and Their Dynamics
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Amanda R. Amori, Zhentao Hou, Todd D. Krauss

    Understanding exciton dynamics in single-walled carbon nanotubes (SWCNTs) is essential to unlocking the many potential applications of these materials. This review summarizes recent progress in understanding exciton photophysics and, in particular, exciton dynamics in SWCNTs. We outline the basic physical and electronic properties of SWCNTs, as well as bright and dark transitions within the framework of a strongly bound one-dimensional excitonic model. We discuss the many facets of ultrafast carrier dynamics in SWCNTs, including both single-exciton states (bright and dark) and multiple-exciton states. Photophysical properties that directly relate to excitons and their dynamics, including exciton diffusion lengths, chemical and structural defects, environmental effects, and photoluminescence photon statistics as observed through photon antibunching measurements, are also discussed. Finally, we identify a few key areas for advancing further research in the field of SWCNT excitons and photonics.

    更新日期:2019-02-26
  • Slow Photoelectron Velocity-Map Imaging of Cryogenically Cooled Anions
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Marissa L. Weichman, Daniel M. Neumark

    Slow photoelectron velocity-map imaging spectroscopy of cryogenically cooled anions (cryo-SEVI) is a powerful technique for elucidating the vibrational and electronic structure of neutral radicals, clusters, and reaction transition states. SEVI is a high-resolution variant of anion photoelectron spectroscopy based on photoelectron imaging that yields spectra with energy resolution as high as 1–2 cm−1. The preparation of cryogenically cold anions largely eliminates hot bands and dramatically narrows the rotational envelopes of spectral features, enabling the acquisition of well-resolved photoelectron spectra for complex and spectroscopically challenging species. We review the basis and history of the SEVI method, including recent experimental developments that have improved its resolution and versatility. We then survey recent SEVI studies to demonstrate the utility of this technique in the spectroscopy of aromatic radicals, metal and metal oxide clusters, nonadiabatic interactions between excited states of small molecules, and transition states of benchmark bimolecular reactions.

    更新日期:2019-02-26
  • Graph Theory and Ion and Molecular Aggregation in Aqueous Solutions
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Jun-Ho Choi, Hochan Lee, Hyung Ran Choi, Minhaeng Cho

    In molecular and cellular biology, dissolved ions and molecules have decisive effects on chemical and biological reactions, conformational stabilities, and functions of small to large biomolecules. Despite major efforts, the current state of understanding of the effects of specific ions, osmolytes, and bioprotecting sugars on the structure and dynamics of water H-bonding networks and proteins is not yet satisfactory. Recently, to gain deeper insight into this subject, we studied various aggregation processes of ions and molecules in high-concentration salt, osmolyte, and sugar solutions with time-resolved vibrational spectroscopy and molecular dynamics simulation methods. It turns out that ions (or solute molecules) have a strong propensity to self-assemble into large and polydisperse aggregates that affect both local and long-range water H-bonding structures. In particular, we have shown that graph-theoretical approaches can be used to elucidate morphological characteristics of large aggregates in various aqueous salt, osmolyte, and sugar solutions. When ion and molecular aggregates in such aqueous solutions are treated as graphs, a variety of graph-theoretical properties, such as graph spectrum, degree distribution, clustering coefficient, minimum path length, and graph entropy, can be directly calculated by considering an ensemble of configurations taken from molecular dynamics trajectories. Here we show percolating behavior exhibited by ion and molecular aggregates upon increase in solute concentration in high solute concentrations and discuss compelling evidence of the isomorphic relation between percolation transitions of ion and molecular aggregates and water H-bonding networks. We anticipate that the combination of graph theory and molecular dynamics simulation methods will be of exceptional use in achieving a deeper understanding of the fundamental physical chemistry of dissolution and in describing the interplay between the self-aggregation of solute molecules and the structure and dynamics of water.

    更新日期:2019-02-26
  • Permutationally Invariant Potential Energy Surfaces
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Chen Qu, Qi Yu, Joel M. Bowman

    Over the past decade, about 50 potential energy surfaces (PESs) for polyatomics with 4–11 atoms and for clusters have been calculated using the permutationally invariant polynomial method. This is a general, mainly linear least-squares method for precise mathematical fitting of tens of thousands of electronic energies for reactive and nonreactive systems. A brief tutorial of the methodology is given, including several recent improvements. Recent applications to the formic acid dimer (the current record holder in size for a reactive system), the H2-H2O complex, and four protonated water clusters [H+(H2O)n=2,3,4,6] are given. The last application also illustrates extension to large clusters using the many-body representation.

    更新日期:2019-02-26
  • Straightening the Hierarchical Staircase for Basis Set Extrapolations: A Low-Cost Approach to High-Accuracy Computational Chemistry
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    António J.C. Varandas

    Because the one-electron basis set limit is difficult to reach in correlated post-Hartree–Fock ab initio calculations, the low-cost route of using methods that extrapolate to the estimated basis set limit attracts immediate interest. The situation is somewhat more satisfactory at the Hartree–Fock level because numerical calculation of the energy is often affordable at nearly converged basis set levels. Still, extrapolation schemes for the Hartree–Fock energy are addressed here, although the focus is on the more slowly convergent and computationally demanding correlation energy. Because they are frequently based on the gold-standard coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)], correlated calculations are often affordable only with the smallest basis sets, and hence single-level extrapolations from one raw energy could attain maximum usefulness. This possibility is examined. Whenever possible, this review uses raw data from second-order Møller–Plesset perturbation theory, as well as CCSD, CCSD(T), and multireference configuration interaction methods. Inescapably, the emphasis is on work done by the author's research group. Certain issues in need of further research or review are pinpointed.

    更新日期:2019-02-26
  • Connections Between Theory and Experiment for Gold and Silver Nanoclusters
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    K.L. Dimuthu M. Weerawardene, Hannu Häkkinen, Christine M. Aikens

    Ligand-stabilized gold and silver nanoparticles are of tremendous current interest in sensing, catalysis, and energy applications. Experimental and theoretical studies have closely interacted to elucidate properties such as the geometric and electronic structures of these fascinating systems. In this review, the interplay between theory and experiment is described; areas such as optical absorption and doping, where the theory–experiment connections are well established, are discussed in detail; and the current status of these connections in newer fields of study, such as luminescence, transient absorption, and the effects of solvent and the surrounding environment, are highlighted. Close communication between theory and experiment has been extremely valuable for developing an understanding of these nanocluster systems in the past decade and will undoubtedly continue to play a major role in future years.

    更新日期:2019-02-26
  • Characterization of Intermediate Oxidation States in CO2 Activation
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Leah G. Dodson, Michael C. Thompson, J. Mathias Weber

    Redox chemistry during the activation of carbon dioxide involves changing the charge state in a CO2 molecular unit. However, such changes are usually not well described by integer formal charges, and one can think of COO functional units as being in intermediate oxidation states. In this article, we discuss the properties of CO2 and CO2-based functional units in various charge states. Besides covering isolated CO2 and its ions, we describe the CO2-based ionic species formate, oxalate, and carbonate. Finally, we provide an overview of CO2-based functional groups and ligands in clusters and metal–organic complexes.

    更新日期:2019-02-26
  • Measuring Electric Fields in Biological Matter Using the Vibrational Stark Effect of Nitrile Probes
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-06-09
    Joshua D. Slocum, Lauren J. Webb

    Measurement of the electrostatic interactions that give rise to biological functions has been a longstanding challenge in biophysics. Advances in spectroscopic techniques over the past two decades have allowed for the direct measurement of electric fields in a wide variety of biological molecules and systems via the vibrational Stark effect (VSE). The frequency of the nitrile stretching oscillation has received much attention as an electric field reporter because of its sensitivity to electric fields and its occurrence in a relatively transparent region of the infrared spectrum. Despite these advantages and its wide use as a VSE probe, the nitrile stretching frequency is sensitive to hydrogen bonding in a way that complicates the straightforward relationship between measured frequency and environmental electric field. Here we highlight recent applications of nitrile VSE probes with an emphasis on experiments that have helped shape our understanding of the determinants of nitrile frequencies in both hydrogen bonding and nonhydrogen bonding environments.

    更新日期:2019-02-26
  • Chemical Kinetics for Bridging Molecular Mechanisms and Macroscopic Measurements of Amyloid Fibril Formation
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Thomas C.T. Michaels, Anđela Šarić, Johnny Habchi, Sean Chia, Georg Meisl, Michele Vendruscolo, Christopher M. Dobson, Tuomas P.J. Knowles

    Understanding how normally soluble peptides and proteins aggregate to form amyloid fibrils is central to many areas of modern biomolecular science, ranging from the development of functional biomaterials to the design of rational therapeutic strategies against increasingly prevalent medical conditions such as Alzheimer's and Parkinson's diseases. As such, there is a great need to develop models to mechanistically describe how amyloid fibrils are formed from precursor peptides and proteins. Here we review and discuss how ideas and concepts from chemical reaction kinetics can help to achieve this objective. In particular, we show how a combination of theory, experiments, and computer simulations, based on chemical kinetics, provides a general formalism for uncovering, at the molecular level, the mechanistic steps that underlie the phenomenon of amyloid fibril formation.

    更新日期:2019-02-26
  • Electronic Transport in Two-Dimensional Materials
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Vinod K. Sangwan, Mark C. Hersam

    Two-dimensional (2D) materials have captured the attention of the scientific community due to the wide range of unique properties at nanometer-scale thicknesses. While significant exploratory research in 2D materials has been achieved, the understanding of 2D electronic transport and carrier dynamics remains in a nascent stage. Furthermore, because prior review articles have provided general overviews of 2D materials or specifically focused on charge transport in graphene, here we instead highlight charge transport mechanisms in post-graphene 2D materials, with particular emphasis on transition metal dichalcogenides and black phosphorus. For these systems, we delineate the intricacies of electronic transport, including band structure control with thickness and external fields, valley polarization, scattering mechanisms, electrical contacts, and doping. In addition, electronic interactions between 2D materials are considered in the form of van der Waals heterojunctions and composite films. This review concludes with a perspective on the most promising future directions in this fast-evolving field.

    更新日期:2019-02-26
  • Vibrational and Nonadiabatic Coherence in 2D Electronic Spectroscopy, the Jahn–Teller Effect, and Energy Transfer
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2016-06-09
    David M. Jonas

    Femtosecond two-dimensional (2D) Fourier transform spectroscopy generates and probes several types of coherence that characterize the couplings between vibrational and electronic motions. These couplings have been studied in molecules with Jahn–Teller conical intersections, pseudo-Jahn–Teller funnels, dimers, molecular aggregates, photosynthetic light harvesting complexes, and photosynthetic reaction centers. All have closely related Hamiltonians and at least two types of vibrations, including one that is decoupled from the electronic dynamics and one that is nonadiabatically coupled. Polarized pulse sequences can often be used to distinguish these types of vibrations. Electronic coherences are rapidly obscured by inhomogeneous dephasing. The longest-lived coherences in these systems arise from delocalized vibrations on the ground electronic state that are enhanced by a nonadiabatic Raman excitation process. These characterize the initial excited-state dynamics. 2D oscillation maps are beginning to isolate the medium lifetime vibronic coherences that report on subsequent stages of the excited-state dynamics.

    更新日期:2019-02-26
  • Enhancing Analytical Separations Using Super-Resolution Microscopy
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Nicholas A. Moringo, Hao Shen, Logan D.C. Bishop, Wenxiao Wang, Christy F. Landes

    Super-resolution microscopy is becoming an invaluable tool to investigate structure and dynamics driving protein interactions at interfaces. In this review, we highlight the applications of super-resolution microscopy for quantifying the physics and chemistry that occur between target proteins and stationary-phase supports during chromatographic separations. Our discussion concentrates on the newfound ability of super-resolved single-protein spectroscopy to inform theoretical parameters via quantification of adsorption-desorption dynamics, protein unfolding, and nanoconfined transport.

    更新日期:2019-02-26
  • Computational Design of Clusters for Catalysis
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Elisa Jimenez-Izal, Anastassia N. Alexandrova

    When small clusters are studied in chemical physics or physical chemistry, one perhaps thinks of the fundamental aspects of cluster electronic structure, or precision spectroscopy in ultracold molecular beams. However, small clusters are also of interest in catalysis, where the cold ground state or an isolated cluster may not even be the right starting point. Instead, the big question is: What happens to cluster-based catalysts under real conditions of catalysis, such as high temperature and coverage with reagents? Myriads of metastable cluster states become accessible, the entire system is dynamic, and catalysis may be driven by rare sites present only under those conditions. Activity, selectivity, and stability are highly dependent on size, composition, shape, support, and environment. To probe and master cluster catalysis, sophisticated tools are being developed for precision synthesis, operando measurements, and multiscale modeling. This review intends to tell the messy story of clusters in catalysis.

    更新日期:2019-02-26
  • Exploring Energy Landscapes
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    David J. Wales

    Recent advances in the potential energy landscapes approach are highlighted, including both theoretical and computational contributions. Treating the high dimensionality of molecular and condensed matter systems of contemporary interest is important for understanding how emergent properties are encoded in the landscape and for calculating these properties while faithfully representing barriers between different morphologies. The pathways characterized in full dimensionality, which are used to construct kinetic transition networks, may prove useful in guiding such calculations. The energy landscape perspective has also produced new procedures for structure prediction and analysis of thermodynamic properties. Basin-hopping global optimization, with alternative acceptance criteria and generalizations to multiple metric spaces, has been used to treat systems ranging from biomolecules to nanoalloy clusters and condensed matter. This review also illustrates how all this methodology, developed in the context of chemical physics, can be transferred to landscapes defined by cost functions associated with machine learning.

    更新日期:2019-02-26
  • Dynamics at Conical Intersections
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Michael S. Schuurman, Albert Stolow

    The nonadiabatic coupling of electronic and vibrational degrees of freedom is the defining feature of electronically excited states of polyatomic molecules. Once considered a theoretical curiosity, conical intersections (CIs) are now generally accepted as being the dominant source of coupled charge and vibrational energy flow in molecular excited states. Passage through CIs leads to the conversion of electronic to vibrational energy, which drives the ensuing photochemistry, isomerization being a canonical example. It has often been remarked that the CI may be thought of as a transition state in the excited state. As such, we expect that both the direction and the velocity of approach to the CI will matter. We explore this suggestion by looking for dynamical aspects of passage through CIs and for analogies with well-known concepts from ground-state reaction dynamics. Great progress has been made in the development of both experimental techniques and ab initio dynamics simulations, to a degree that direct comparisons may now be made. Here we compare time-resolved photoelectron spectroscopy results with on-the-fly ab initio multiple spawning calculations of the experimental observables, thereby validating each. We adopt a phenomenological approach and specifically concentrate on the excited-state dynamics of the C=C bond in unsaturated hydrocarbons. In particular, we make use of selective chemical substitution (such as replacing an H atom by a methyl group) so as to alter the inertia of certain vibrations relative to others, thus systematically varying (mass-weighted) directions and velocities of approach to a CI. Chemical substituents, however, may affect both the nuclear and electronic components of the total wave function. The former, which we call an inertial effect, influences the direction and velocity of approach. The latter, which we call a potential effect, modifies the electronic structure and therefore the energetic location and topography of the potential energy surfaces involved. Using a series of examples, we discuss both types of effects. We argue that there is a need for dynamical pictures and simple models of nonadiabatic dynamics at CIs and hope that the phenomenology presented here will help inspire such developments.

    更新日期:2019-02-26
  • Elementary Chemical Reactions in Surface Photocatalysis
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Qing Guo, Chuanyao Zhou, Zhibo Ma, Zefeng Ren, Hongjun Fan, Xueming Yang

    Photocatalytic hydrogen evolution and organic degradation on oxide materials have been extensively investigated in the last two decades. Great efforts have been dedicated to the study of photocatalytic reaction mechanisms of a variety of molecules on TiO2 surfaces by using surface science methods under ultra-high vacuum (UHV) conditions, providing fundamental understanding of surface chemical reactions in photocatalysis. In this review, we summarize the recent progress in the study of photocatalysis of several important species (water, methanol, and aldehydes) on different TiO2 surfaces. The results of these studies have provided us deep insights into the elementary processes of surface photocatalysis and stimulated a new frontier of research in this area. Based on the results of these studies, a new dynamics-based photocatalysis model is also discussed.

    更新日期:2019-02-26
  • Computational Photophysics in the Presence of an Environment
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Juan J. Nogueira, Leticia González

    Most processes triggered by ultraviolet (UV) or visible (vis) light in nature take place in complex biological environments. The first step in these photophysical events is the excitation of the absorbing system or chromophore to an electronically excited state. Such an excitation can be monitored by the UV-vis absorption spectrum. A precise calculation of the UV-vis spectrum of a chromophore embedded in an environment is a challenging task that requires the consideration of several ingredients, besides an accurate electronic-structure method for the excited states. Two of the most important are an appropriate description of the interactions between the chromophore and the environment and accounting for the vibrational motion of the whole system. In this contribution, we review the most common theoretical methodologies to describe the environment (including quantum mechanics/continuum and quantum mechanics/molecular mechanics models) and to account for vibrational sampling (including Wigner sampling and molecular dynamics). Further, we illustrate in a series of examples how the lack of these ingredients can lead to a wrong interpretation of the electronic features behind the UV-vis absorption spectrum.

    更新日期:2019-02-26
  • Sensing Chirality with Rotational Spectroscopy
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Sérgio R. Domingos, Cristóbal Pérez, Melanie Schnell

    Chiroptical spectroscopy techniques for the differentiation of enantiomers in the condensed phase are based on an established paradigm that relies on symmetry breaking using circularly polarized light. We review a novel approach for the study of chiral molecules in the gas phase using broadband rotational spectroscopy, namely microwave three-wave mixing, which is a coherent, nonlinear, and resonant process. This technique can be used to generate a coherent molecular rotational signal that can be detected in a manner similar to that in conventional Fourier transform microwave spectroscopy. The structure (and thermal distribution of conformations), handedness, and enantiomeric excess of gas-phase samples can be determined unambiguously by employing tailored microwave fields. We discuss the theoretical and experimental aspects of the method, the significance of the first demonstrations of the technique for enantiomer differentiation, and the method's rapid advance into a robust choice to study molecular chirality in the gas phase. Very recently, the microwave three-wave mixing approach was extended to enantiomer-selective population transfer, an important step toward spatial enantiomer separation on the fly.

    更新日期:2019-02-26
  • Membrane-Mediated Cooperativity of Proteins
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2018-04-20
    Thomas R. Weikl

    Besides direct protein–protein interactions, indirect interactions mediated by membranes play an important role for the assembly and cooperative function of proteins in membrane shaping and adhesion. The intricate shapes of biological membranes are generated by proteins that locally induce membrane curvature. Indirect curvature-mediated interactions between these proteins arise because the proteins jointly affect the bending energy of the membranes. These curvature-mediated interactions are attractive for crescent-shaped proteins and are a driving force in the assembly of the proteins during membrane tubulation. Membrane adhesion results from the binding of receptor and ligand proteins that are anchored in the apposing membranes. The binding of these proteins strongly depends on nanoscale shape fluctuations of the membranes, leading to a fluctuation-mediated binding cooperativity. A length mismatch between receptor–ligand complexes in membrane adhesion zones causes repulsive curvature-mediated interactions that are a driving force for the length-based segregation of proteins during membrane adhesion.

    更新日期:2019-02-26
  • Molecules at Solid Surfaces: A Personal Reminiscence
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    Gerhard Ertl

    I was fortunate to start my career in physical chemistry at a time when the development of the ultrahigh vacuum technique and of novel physical methods enabled the study of processes on well-defined surfaces at an atomic scale. These investigations included the mechanisms of heterogeneously catalyzed reactions, such as CO oxidation and ammonia synthesis, and phenomena of spatio-temporal self-organization, as described by the concepts of nonlinear dynamics.

    更新日期:2018-02-22
  • From 50 Years Ago, the Birth of Modern Liquid-State Science
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    David Chandler

    The story told in this autobiographical perspective begins 50 years ago, at the 1967 Gordon Research Conference on the Physics and Chemistry of Liquids. It traces developments in liquid-state science from that time, including contributions from the author, and especially in the study of liquid water. It emphasizes the importance of fluctuations and the challenges of far-from-equilibrium phenomena.

    更新日期:2018-02-22
  • Quantum State–Resolved Studies of Chemisorption Reactions
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    Helen Chadwick, Rainer D. Beck

    Chemical reactions at the gas–surface interface are ubiquitous in the chemical industry as well as in nature. Investigating these processes at a microscopic, quantum state–resolved level helps develop a predictive understanding of this important class of reactions. In this review, we present an overview of the field of quantum state–resolved gas–surface reactivity measurements that explore the role of the initial quantum state on the dissociative chemisorption of a gas-phase reactant incident on a solid surface. Using molecular beams and either quantum state–specific reactant preparation or product detection by laser excitation, these studies have observed mode specificity and bond selectivity as well as steric effects in chemisorption reactions, highlighting the nonstatistical and complex nature of gas–surface reaction dynamics.

    更新日期:2018-02-22
  • Molecular Photofragmentation Dynamics in the Gas and Condensed Phases
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    Michael N.R. Ashfold, Daniel Murdock, Thomas A.A. Oliver

    Exciting a molecule with an ultraviolet photon often leads to bond fission, but the final outcome of the bond cleavage is typically both molecule and phase dependent. The photodissociation of an isolated gas-phase molecule can be viewed as a closed system: Energy and momentum are conserved, and the fragmentation is irreversible. The same is not true in a solution-phase photodissociation process. Solvent interactions may dissipate some of the photoexcitation energy prior to bond fission and will dissipate any excess energy partitioned into the dissociation products. Products that have no analog in the corresponding gas-phase study may arise by, for example, geminate recombination. Here, we illustrate the extent to which dynamical insights from gas-phase studies can inform our understanding of the corresponding solution-phase photochemistry and how, in the specific case of photoinduced ring-opening reactions, solution-phase studies can in some cases reveal dynamical insights more clearly than the corresponding gas-phase study.

    更新日期:2018-02-22
  • Coherent Light Sources at the Nanoscale
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    Ankun Yang, Danqing Wang, Weijia Wang, Teri W. Odom

    This review focuses on coherent light sources at the nanoscale, and specifically on lasers exploiting plasmonic cavities that can beat the diffraction limit of light. Conventional lasers exhibit coherent, intense, and directional emission with cavity sizes much larger than their operating wavelength. Plasmon lasers show ultrasmall mode confinement, support strong light–matter interactions, and represent a class of devices with extremely small sizes. We discuss the differences between plasmon lasers and traditional ones, and we highlight advances in directionality and tunability through innovative cavity designs and new materials. Challenges and future prospects are also discussed.

    更新日期:2018-02-22
  • Progress Toward a Molecular Mechanism of Water Oxidation in Photosystem II
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    David J. Vinyard, Gary W. Brudvig

    The active site of photosynthetic water oxidation is the oxygen-evolving complex (OEC) in the photosystem II (PSII) reaction center. The OEC is a Mn4CaO5 cluster embedded in the PSII protein matrix, and it cycles through redox intermediates known as Si states (i = 0–4). Significant progress has been made in understanding the inorganic and physical chemistry of states S0–S3 through experiment and theory. The chemical steps from S3 to S0 are more poorly understood, however, because the identity of the substrate water molecules and the mechanism of O–O bond formation are not well established. In this review, we highlight both the consensuses and the remaining challenges of PSII research.

    更新日期:2018-02-22
  • Computer Simulations of Intrinsically Disordered Proteins
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    Song-Ho Chong, Prathit Chatterjee, Sihyun Ham

    The investigation of intrinsically disordered proteins (IDPs) is a new frontier in structural and molecular biology that requires a new paradigm to connect structural disorder to function. Molecular dynamics simulations and statistical thermodynamics potentially offer ideal tools for atomic-level characterizations and thermodynamic descriptions of this fascinating class of proteins that will complement experimental studies. However, IDPs display sensitivity to inaccuracies in the underlying molecular mechanics force fields. Thus, achieving an accurate structural characterization of IDPs via simulations is a challenge. It is also daunting to perform a configuration-space integration over heterogeneous structural ensembles sampled by IDPs to extract, in particular, protein configurational entropy. In this review, we summarize recent efforts devoted to the development of force fields and the critical evaluations of their performance when applied to IDPs. We also survey recent advances in computational methods for protein configurational entropy that aim to provide a thermodynamic link between structural disorder and protein activity.

    更新日期:2018-02-22
  • QM/MM Geometry Optimization on Extensive Free-Energy Surfaces for Examination of Enzymatic Reactions and Design of Novel Functional Properties of Proteins
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    Shigehiko Hayashi, Yoshihiro Uchida, Taisuke Hasegawa, Masahiro Higashi, Takahiro Kosugi, Motoshi Kamiya

    Many remarkable molecular functions of proteins use their characteristic global and slow conformational dynamics through coupling of local chemical states in reaction centers with global conformational changes of proteins. To theoretically examine the functional processes of proteins in atomic detail, a methodology of quantum mechanical/molecular mechanical (QM/MM) free-energy geometry optimization is introduced. In the methodology, a geometry optimization of a local reaction center is performed with a quantum mechanical calculation on a free-energy surface constructed with conformational samples of the surrounding protein environment obtained by a molecular dynamics simulation with a molecular mechanics force field. Geometry optimizations on extensive free-energy surfaces by a QM/MM reweighting free-energy self-consistent field method designed to be variationally consistent and computationally efficient have enabled examinations of the multiscale molecular coupling of local chemical states with global protein conformational changes in functional processes and analysis and design of protein mutants with novel functional properties.

    更新日期:2018-02-22
  • Development of New Density Functional Approximations
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    Neil Qiang Su, Xin Xu

    Kohn–Sham density functional theory has become the leading electronic structure method for atoms, molecules, and extended systems. It is in principle exact, but any practical application must rely on density functional approximations (DFAs) for the exchange-correlation energy. Here we emphasize four aspects of the subject: (a) philosophies and strategies for developing DFAs; (b) classification of DFAs; (c) major sources of error in existing DFAs; and (d) some recent developments and future directions.

    更新日期:2018-02-22
  • Criegee Intermediates: What Direct Production and Detection Can Teach Us About Reactions of Carbonyl Oxides
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    Craig A. Taatjes

    The carbonyl oxide intermediates in the ozonolysis of alkenes, often known as Criegee intermediates, are potentially important reactants in Earth's atmosphere. For decades, careful analysis of ozonolysis systems was employed to derive an understanding of the formation and reactions of these species. Recently it has proved possible to synthesize at least some of these intermediates separately from ozonolysis, and hence to measure their reaction kinetics directly. Direct measurements have allowed new or more detailed understanding of each type of gas-phase reaction that carbonyl oxides undergo, often acting as a complement to highly detailed ozonolysis experiments. Moreover, the use of direct characterization methods to validate increasingly accurate theoretical investigations can enhance their impact well beyond the set of specific reactions that have been measured. Reactions that initiate particles or fuel their growth could be a new frontier for direct measurements of Criegee intermediate chemistry.

    更新日期:2018-02-22
  • Water Oxidation Mechanisms of Metal Oxide Catalysts by Vibrational Spectroscopy of Transient Intermediates
    Annu. Rev. Phys. Chem. (IF 11.982) Pub Date : 2017-05-02
    Miao Zhang, Heinz Frei

    Water oxidation is an essential reaction of an artificial photosystem for solar fuel generation because it provides electrons needed to reduce carbon dioxide or protons to a fuel. Earth-abundant metal oxides are among the most attractive catalytic materials for this reaction because of their robustness and scalability, but their efficiency poses a challenge. Knowledge of catalytic surface intermediates gained by vibrational spectroscopy under reaction conditions plays a key role in uncovering kinetic bottlenecks and provides a basis for catalyst design improvements. Recent dynamic infrared and Raman studies reveal the molecular identity of transient surface intermediates of water oxidation on metal oxides. Combined with ultrafast infrared observations of how charges are delivered to active sites of the metal oxide catalyst and drive the multielectron reaction, spectroscopic advances are poised to play a key role in accelerating progress toward improved catalysts for artificial photosynthesis.

    更新日期:2018-02-22
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