Spiers Memorial Lecture : Introductory lecture: Hot-electron science and microscopic processes in plasmonics and catalysis

2019 ◽  
Vol 214 ◽  
pp. 13-33 ◽  
Author(s):  
N. J. Halas
Keyword(s):  
Chemical Reactions ◽  
Memorial Lecture ◽  
Hot Electron ◽  
Introductory Lecture

In these introductory remarks we discuss the generation of nonequilibrium electrons in metals, their properties, and how they can be utilized in two emerging applications: for extending the capabilities of photodetection (left), and for photocatalysis (right), lowering the barriers of chemical reactions.

scholarly journals Spiers Memorial Lecture : Introductory lecture: quantum dynamics of chemical reactions

2018 ◽  
Vol 212 ◽  
pp. 9-32 ◽  
Author(s):  
David C. Clary
Keyword(s):  
Small Molecules ◽  
Chemical Reactions ◽  
Quantum Dynamics ◽  
Quantum Effects ◽  
Memorial Lecture ◽  
Introductory Lecture

This Spiers Memorial Lecture discusses quantum effects that can be calculated and observed in the chemical reactions of small molecules.

scholarly journals New solar energy-storage resource of plasmon-activated water solution with higher chemical potential

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chih-Ping Yang ◽  
Shih-Hao Yu ◽  
Fu-Der Mai ◽  
Tai-Chih Kuo ◽  
Yu-Chuan Liu
Keyword(s):  
Energy Storage ◽  
Solar Energy ◽  
Chemical Reactions ◽  
Chemical Potential ◽  
Water Solution ◽  
Storage System ◽  
Energy Storage System ◽  
Hot Electron ◽  
Energy Storage Devices ◽  
Innovative Strategy

AbstractNowadays, solar energy is the most environmentally friendly energy source to drive many chemical reactions and physical processes. However, the corresponding fabrication procedures for obtaining excellent energy-storage devices are relatively complicated and expensive. In this work, we report an innovative strategy on plasmon-activated water (PAW) serving as energy-storage medium from solar energy. The lifetime of the created energetic PAW solution from hot electron transfer (HET) on Au nanoparticles (AuNPs) illuminated with sunshine can last for 2 days, making the energy-storage system is practically available. Encouragingly, the energy-conversion efficiency from the solar energy in the PAW solution is ca. 6.7%. Compared to conventional deionized (DI) water solution, the prepared metastable PAW solution exhibited distinctly higher chemical potential at room temperature. It demonstrates abilities in faster evaporation and enhancing chemical reactions, including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Our proposed strategy on the simple and cheap energy-storage system based on prepared PAW utilizing solar energy is the first time shown in the literature.

scholarly journals Spiers Memorial Lecture : Introductory lecture: the impact of structure on photoinduced processes in nucleic acids and proteins

2018 ◽  
Vol 207 ◽  
pp. 9-26
Author(s):  
Tatiana Domratcheva ◽  
Ilme Schlichting
Keyword(s):  
Nucleic Acids ◽  
Memorial Lecture ◽  
Introductory Lecture ◽  
The Impact ◽  
Photoinduced Processes

This review gives an overview of the impact of structure on the understanding of photoinduced processes in macromolecules, focusing on systems presented at this Faraday Discussion meeting.

scholarly journals Understanding the Mechanism of Plasmon-Driven Water Splitting: Hot Electron Injection and Near Field Enhancement Effects

2021 ◽  
Author(s):  
Jiaquan Huang ◽  
Xinyi Zhao ◽  
Xunkun Huang ◽  
Wanzhen Liang
Keyword(s):  
Water Splitting ◽  
Chemical Reactions ◽  
Reaction Rate ◽  
Near Field ◽  
Electron Injection ◽  
Model Systems ◽  
Au Nanoparticle ◽  
Hot Electron ◽  
Hot Carriers ◽  
Hot Electron Injection

Utilizing plasmon-generated hot carriers to drive chemical reactions has currently become an active area of research in solar photocatalysis at the nanoscale. However, the mechanism underlying exact transfer and the generation dynamics of hot carriers, and the strategies used to further improve the quantum efficiency of the photocatalytic reaction still deserve a further look. In this work, we perform a nonadiabatic excited-state dynamics study to depict the correlation between the reaction rate of plasmon-driven water splitting (PDWS) and the sizes of gold particles, the incident light frequency and intensity, and the near-field's spatial distribution. Four model systems, \ce{H2O} and \ce{Au20}@\ce{H2O} separately interacting with the laser field and the near field generated by the Au nanoparticle (NP) with a few nanometers in size, have been investigated. Our simulated results clearly unveil the mechanism of PDWS and hot-electron injection in a Schottky-free junction: the electrons populated on the antibonding orbitals of \ce{H2O} are mandatory to drive the \ce{OH} bond breaking and the strong orbital hybridization between \ce{Au20} and \ce{H2O} creates the condition for direct electron injection. We further find that the linear dependence of the reaction rate and the field amplitude only holds at a relatively weak field and it breaks down when the second {\ce{OH}} bond begins to dissociate and field-induced water fragmenting at a very intensive field, and that with the guarantee of electron injection, the water splitting rate increases with the increase of NP's size. This study will be helpful for further improving the efficiency of the photochemical reactions involving the plasmon-generated hot carriers and expanding the applications of hot carriers in varieties of chemical reactions.

Progress report on 21-cm observations at low latitude between longitudes (l 11) 0° and 66°

1967 ◽  
Vol 31 ◽  
pp. 177-179
Author(s):  
W. W. Shane
Keyword(s):  
Preliminary Report ◽  
Progress Report ◽  
Galactic Centre ◽  
Low Latitude ◽  
The Third ◽  
Introductory Lecture ◽  
Centre Region

In the course of several 21-cm observing programmes being carried out by the Leiden Observatory with the 25-meter telescope at Dwingeloo, a fairly complete, though inhomogeneous, survey of the regionl11= 0° to 66° at low galactic latitudes is becoming available. The essential data on this survey are presented in Table 1. Oort (1967) has given a preliminary report on the first and third investigations. The third is discussed briefly by Kerr in his introductory lecture on the galactic centre region (Paper 42). Burton (1966) has published provisional results of the fifth investigation, and I have discussed the sixth in Paper 19. All of the observations listed in the table have been completed, but we plan to extend investigation 3 to a much finer grid of positions.

Surface reactions observed by photoemission electron microscopy (PEEM)

1992 ◽  
Vol 50 (1) ◽  
pp. 286-287
Author(s):  
H.H. Rotermund
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Work Function ◽  
Chemical Reactions ◽  
Reaction Diffusion ◽  
Dynamic Processes ◽  
Clean Surface ◽  
Crystal Surfaces ◽  
Single Crystal Surfaces ◽  
Photoemission Electron

Chemical reactions at a surface will in most cases show a measurable influence on the work function of the clean surface. This change of the work function δφ can be used to image the local distributions of the investigated reaction,.if one of the reacting partners is adsorbed at the surface in form of islands of sufficient size (Δ>0.2μm). These can than be visualized via a photoemission electron microscope (PEEM). Changes of φ as low as 2 meV give already a change in the total intensity of a PEEM picture. To achieve reasonable contrast for an image several 10 meV of δφ are needed. Dynamic processes as surface diffusion of CO or O on single crystal surfaces as well as reaction / diffusion fronts have been observed in real time and space.

Microwaves: Application in Electron Microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 140-141
Author(s):  
Anthony S-Y Leong ◽  
David W Gove
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Tissue Fixation ◽  
Primary Method ◽  
Dipolar Molecules ◽  
Wide Range ◽  
Time Required ◽  
Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

Fine structure and properties of defects in naturally occurring silicates and oxides

1990 ◽  
Vol 48 (4) ◽  
pp. 460-461
Author(s):  
David R. Veblen
Keyword(s):  
Chemical Reactions ◽  
High Resolution Electron Microscopy ◽  
Extended Defects ◽  
Single Chain ◽  
Naturally Occurring ◽  
Resolution Electron ◽  
Fine Structures ◽  
Image Simulations ◽  
Similar Crystal Structure

Extended defects and interfaces control many processes in rock-forming minerals, from chemical reactions to rock deformation. In many cases, it is not the average structure of a defect or interface that is most important, but rather the structure of defect terminations or offsets in an interface. One of the major thrusts of high-resolution electron microscopy in the earth sciences has been to identify the role of defect fine structures in reactions and to determine the structures of such features. This paper will review studies using HREM and image simulations to determine the structures of defects in silicate and oxide minerals and present several examples of the role of defects in mineral chemical reactions. In some cases, the geological occurrence can be used to constrain the diffusional properties of defects.The simplest reactions in minerals involve exsolution (precipitation) of one mineral from another with a similar crystal structure, and pyroxenes (single-chain silicates) provide a good example. Although conventional TEM studies have led to a basic understanding of this sort of phase separation in pyroxenes via spinodal decomposition or nucleation and growth, HREM has provided a much more detailed appreciation of the processes involved.

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