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In physics, electron emission is the ejection of an electron from the surface of matter, [1] or, in beta decay (β− decay), where a beta particle (a fast energetic electron or positron) is emitted from an atomic nucleus transforming the original nuclide to an isobar.
In this regime, the combined effects of field-enhanced thermionic and field emission can be modeled by the Murphy-Good equation for thermo-field (T-F) emission. [35] At even higher fields, FN tunneling becomes the dominant electron emission mechanism, and the emitter operates in the so-called "cold field electron emission (CFE)" regime.
Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, solid state, and quantum chemistry to draw inferences about the properties of atoms, molecules and solids. The effect has found use in electronic devices specialized for light detection and precisely timed electron emission.
However, meaningful investigations had to wait until after J.J. Thomson's [3] identification of the electron in 1897, and until after it was understood – from thermal emission [4] and photo-emission [5] work – that electrons could be emitted from inside metals (rather than from surface-adsorbed gas molecules), and that – in the absence of ...
The term −eϕ is the energy of an electron at rest in the vacuum nearby the surface. Plot of electron energy levels against position, in a gold-vacuum-aluminium system. The two metals depicted here are in complete thermodynamic equilibrium. However, the vacuum electrostatic potential ϕ is not flat due to a difference in work function.
Emission spectrum of a ceramic metal halide lamp. A demonstration of the 589 nm D 2 (left) and 590 nm D 1 (right) emission sodium D lines using a wick with salt water in a flame The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to electrons making a ...
Each incident electron produces multiple secondary electrons, so the cascaded dynode chain amplifies the initial electrons. In particle physics , secondary emission is a phenomenon where primary incident particles of sufficient energy , when hitting a surface or passing through some material, induce the emission of secondary particles.
The Schottky effect or field enhanced thermionic emission is a phenomenon in condensed matter physics named after Walter H. Schottky.In electron emission devices, especially electron guns, the thermionic electron emitter will be biased negative relative to its surroundings.