Initial spatial distribution of localized electrons under laser ionization of athracene in methylcyclohexane determined by the picosecond photo-assisted charge separation technique

1996 ◽  
Author(s):  
F. F. Brazgun ◽  
Victor A. Nadtochenko ◽  
Igor V. Rubtsov ◽  
L. V. Lukin
Keyword(s):  
Spatial Distribution ◽  
Charge Separation ◽  
Separation Technique ◽  
Laser Ionization ◽  
Initial Spatial Distribution ◽  
Localized Electrons

Kinetic energy and spatial distribution of ions in high irradiance laser ionization source

2011 ◽  
Vol 26 (6) ◽  
pp. 1183 ◽  
Author(s):  
Yiming Lin ◽  
Ruibin Xu ◽  
Lingfeng Li ◽  
Wei Hang ◽  
Jian He ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Kinetic Energy ◽  
High Irradiance ◽  
Laser Ionization ◽  
Ionization Source

Spatial distribution of active sites on a ferroelectric PbTiO3 photocatalyst for photocatalytic hydrogen production

2017 ◽  
Vol 198 ◽  
pp. 463-472 ◽  
Author(s):  
Rengui Li ◽  
Yue Zhao ◽  
Can Li
Keyword(s):  
Spatial Distribution ◽  
Hydrogen Production ◽  
Solar Energy ◽  
Energy Conversion ◽  
Electric Fields ◽  
Charge Separation ◽  
Active Sites ◽  
Solar Energy Conversion ◽  
Photogenerated Electrons ◽  
The Right

The separation of photogenerated charge carries is a challenging issue in artificial photocatalyst systems for solar energy conversion. It has been reported that spatial charge separation can take place between different facets of semiconductor-based crystals with regular morphology and facets, which could be used to rationally deposit cocatalysts on the right facets. However, the spatial separation of photogenerated electrons and holes is still a big challenge for a particulate photocatalyst without regular morphology and specific facets. In this work, we demonstrated that photogenerated electrons and holes can be regularly separated on ferroelectric PbTiO3 photocatalyst even without regular morphology and facets. The reduction cocatalyst and oxidation cocatalyst could be selectively formed on different sites via an in situ photochemical deposition method. It is found that the photoactivity and hydrogen production for PbTiO3 with spatially separated dual-cocatalysts is remarkably enhanced to more than 100 times greater compared to native PbTiO3, which is much higher than that the case of dual-cocatalysts with a random distribution. The intrinsic electric fields and spontaneous electric polarization in the bulk of PbTiO3 are proposed to play important roles in the spatial distribution of active sites on irregular PbTiO3 particles. Our work emphasizes the essential roles of two important factors, efficient charge separation strategy and the location of dual-cocatalysts on the right sites, to construct integrated artificial photocatalyst systems for solar energy conversion.

Kinetics of nonhomogeneous chemical processes in tracks of high-energy charged particles

1990 ◽  
Vol 68 (9) ◽  
pp. 858-871 ◽  
Author(s):  
A. Hummel
Keyword(s):  
Spatial Distribution ◽  
Large Fraction ◽  
Charged Particles ◽  
Coulomb Field ◽  
High Energy ◽  
Transient Species ◽  
Charged Species ◽  
Solvent Molecules ◽  
Kinetics Of ◽  
Initial Spatial Distribution

High-energy charged particles, when slowing down in a molecular medium, lose their energy by electronic excitations and ionizations of molecules along their paths. If the secondary electrons that are formed as a result of the ionizations have sufficient energy, they give rise to further excitations and ionizations. In this way tracks of excited states, positive ions, and electrons are formed. The spatial distribution of the species initially formed in the track will change in time owing to diffusion; the charged species will also drift in each other's Coulomb field. In nonpolar systems the range of the Coulomb forces is very large (30 nm) and neutralization of the oppositely charged species in the track is a dominant process, which in turn leads to formation of excited molecules that generally decompose into reactive fragments. In polar liquids, like water, neutralization is less prevalent and a relatively large fraction of the charged species escapes from the Coulombic attraction. The transient species formed may react with one another and with molecules of the medium, either solvent molecules or solute molecules. The probability of the occurrence of these reactions depends on the initial spatial distribution of the reactive species in the track. The present state of the theory of the kinetics of the nonhomogeneous processes in tracks of high-energy charged particles, which relates the initial spatial distribution of the transient species in the track to the various experimental observables, will be discussed.

scholarly journals Extinction of Bistable Populations is Affected by the Shape of their Initial Spatial Distribution

2021 ◽  
Vol 84 (1) ◽  
Author(s):  
Yifei Li ◽  
Stuart T. Johnston ◽  
Pascal R. Buenzli ◽  
Peter van Heijster ◽  
Matthew J. Simpson
Keyword(s):  
Spatial Distribution ◽  
Initial Spatial Distribution

scholarly journals Charge separation technique for metal–oxide–silicon capacitors in the presence of hydrogen deactivated dopants

2000 ◽  
Vol 87 (11) ◽  
pp. 8206-8208 ◽  
Author(s):  
Steven C. Witczak ◽  
Peter S. Winokur ◽  
Ronald C. Lacoe ◽  
Donald C. Mayer
Keyword(s):  
Metal Oxide ◽  
Charge Separation ◽  
Separation Technique ◽  
Metal Oxide Silicon

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

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