Swift electrons

Field-ion Microscopy , Defects In Crystalline Solids Series, 2, North Hoiland Pub Co. (1970) 43) J.A. Swift, Electron Microscopes , Barnes Noble Publ (1970) 44) W.E. Voreck,... 

In the (semi-)classical models of ETR (Marcus the Russian school), redox orbitals of reactants overlap at a close separation, followed by swift electron transfer. The activated complex, considered in equilibrium with the reactants, consists of these overlapping orbitals. In the tunneling model, the electron penetrates... 

Single-plasmon contributions to the electron inelastic mean free path of swift electrons have been calculated for many years, both in the high-velocity limit... 

This approximation is valid for heavy charged particles, e.g., ions, and also for swift electrons moving with velocities that are large compared to those of the electrons in the medium. In the case of electrons, Zj = — 1. 

The answer to this question is in three parts. The first part is related to the properties of the electron probe, such as the size of the probe and its broadening, as well as the impact parameter problem, i.e. the characteristic distance beyond which the influence of the electric field from the swift electrons is negligible. The second part is more a specimen problem, namely the spatial... 

There are two questions which arise on this topic (1) What is the fate of the swift electrons that are generated during the absorption of high-energy photons. (2) How do high-energy electrons of an electron beam interact with matter. ... 

C-term Owing to the considerable difference in the masses involved, very little energy is transferred from the swift electron to the atomic nucleus. Only electrons of very high energy are capable of chemical change by direct displacement of the nucleus during collision acts. 

Fig. IV-18. (a) Electron micrograph of a collapsing film of 2-hydroxytetracosanoic acid. Scale bar 1. [From H. E. Ries, Jr., Nature, 281, 287 (1979).] (b) Possible collapse mechanism. [Reprinted with permission from H. E. Ries, Jr. and H. Swift, Langmuir, 3, 853 (1987) (Ref. 223). Copyright 1987, American Chemical Society.]...

In both electron post-ionization techniques mass analysis is performed by means of a quadrupole mass analyzer (Sect. 3.1.2.2), and pulse counting by means of a dynode multiplier. In contrast with a magnetic sector field, a quadrupole enables swift switching between mass settings, thus enabling continuous data acquisition for many elements even at high sputter rates within thin layers. 

The enantioselective inverse electron-demand 1,3-dipolar cycloaddition reactions of nitrones with alkenes described so far were catalyzed by metal complexes that favor a monodentate coordination of the nitrone, such as boron and aluminum complexes. However, the glyoxylate-derived nitrone 36 favors a bidentate coordination to the catalyst. This nitrone is a very interesting substrate, since the products that are obtained from the reaction with alkenes are masked a-amino acids. One of the characteristics of nitrones such as 36, having an ester moiety in the a position, is the swift E/Z equilibrium at room temperature (Scheme 6.28). In the crystalline form nitrone 36 exists as the pure Z isomer, however, in solution nitrone 36 have been shown to exists as a mixture of the E and Z isomers. This equilibrium could however be shifted to the Z isomer in the presence of a Lewis acid [74]. 

Inelastic collisions of swift, charged particles with matter are completely described by the distribution of generalized oscillator strengths (GOS s) characterizing the collision. These quantities, characteristic of excitation in the N-electron target (or, in fact, of a dressed projectile as well [1]) from some initial state 0) to a final state n) and concomitant momentum transfer, can be written... 

The technique employs a beam of swift (-500kV) electrons grazing the surface of interest. Provided that the beam is accurately aligned along a crystal zone axis, and that the electron-optical imaging system is adequate, then images are obtained which appear to show the atomic surface structure in profile (see Figure 1). 

The picture of cement microstructure that now emerges is of particles of partially degraded glass embedded in a matrix of calcium and aluminium polyalkenoates and sheathed in a layer of siliceous gel probably formed just outside the particle boundary. This structure (shown in Figure 5.17) was first proposed by Wilson Prosser (1982, 1984) and has since been confirmed by recent electron microscopic studies by Swift Dogan (1990) and Hatton Brook (1992). The latter used transmission electron microscopy with high resolution to confirm this model without ambiguity. 

Swift, E. J. Dogan, A. U. (1990). Analysis of glass-ionomer cement with use of scanning electron microscopy. Journal of Prosthetic Dentistry, 64, 167-74. 

Streams of swiftly moving electrons given off by some radioactive substances they are used in beta ray gauges which give continuous measurement of the thickness of films of rubber or plastics. 

As a rule of thumb , reversibility (in the electrochemical sense) implies that the electron-transfer reaction is sufficiently swift for the current to obey equation (6.6) instantly and that no chemical processes accompany the electron-transfer reaction - see Section 6.3.4. 

We consider here the orientational aspects of the stopping of swift protons by the water molecule. The calculations are dynamical in nature, and they are compared to the electronic structure-based calculations made by Oddershede et al. on similar quantities. The comparisons, although qualitative, show good agreement between the two approaches. 

ESR methods unambiguously establishes the presence of species bearing unpaired electrons (ion-radicals and radicals). The ESR spectrum quantitatively characterizes the distribution of electron density within the paramagnetic particle by a hyperfine structure of ESR spectra. This establishes the nature and electronic configuration of the particle. A review by Davies (2001) is highly recommended as a guide to current practice for ESR spectroscopic studies (this quotation is from the title of the review). The ESR method dominates in ion-radical studies. Its modern modifications, namely, ENDOR and electron-nuclear-nuclear triple resonance (TRIPLE) and special methods to observe ion-radicals by swiftness or stealth are described in special literatures (Moebius and Biehl 1979, Kurreck et al. 1988, Werst and Trifunac 1998). 

Several students and associates of Rutherford attempted to make and detect neutrons by these means or via swift protons produeed in nuelear reaetions indueed by a particles protons and electrons were given opportunities to smash into eaeh other. These efforts did not lead to the discovery of the neutron. 

Number of Particle Families. How many families of matter may exist Three, four, or more An acceptable number among researchers today is three, Three family entities make up matter—the stars, the planets, molecules, and the atoms in the paper upon which this is printed. These fundamental particles are the up1 quark, the down quark, and the electron,. Some other researchers are not quite so confident. One is reminded of the quotation from Jonathan Swift ... 

In Table 1 is shown the cold electron emission current calculated by Bethe and Zommerfeld [32] with allowance for the image potential. One can see that in fields of several million volts per centimeter the electron current initially jumps but then swiftly reaches very high values. Experimentally, a... 

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