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Electron Affinity

Amount of energy released when an electron is added to element to create anion.

Electron Diffraction

Electron diffraction is a collective scattering phenomenon with electrons being (nearly elastically) scattered by atoms in a regular array (crystal). This can be understood in analogy to the Huygens principle for the diffraction of light. The incoming plane electron wave interacts with the atoms, and secondary waves are generated which interfere with each other. This occurs either constructively (reinforcement at certain scattering angles generating diffracted beams) or destructively (extinguishing of beams). 

Electron Gas

Free electrons behavior in vacuum or metallic conductor.

Electron Gun

Arrangement to produce a fine beam of electrons accelerated to desired velocity.

Electron-Ion Pair

Ionization is the process of removing one or more electrons from a neutral atom. This results in the loss of units of negative charge by the affected atom. The atom becomes electrically positive (a positive ion). The products of a single ionizing event are called an electron-ion pair.

Electron Lens

It is a system which uses both electric and magnetic fields to focus a beam of electrons.

Electron Mass

Rest mass of electron is one of the fundamental constants of Physics. It is the mass of rest electron, the value of which is  9.11x10-31 Kg or ~ 0.51MeV/C2.

Electron Microscope

The electron microscope is a type of microscope that uses a beam of electrons to create an image of the specimen. It is capable of much higher magnifications and has a greater resolving power than an optical microscope, allowing it to see much smaller objects in free details.

Electron Microscopy

Technique used to study the microstructure details of crystalline specimen. Electron microscope is capable of obtaining higher magnification. An image of structure under investigation is formed using beams of electrons instead of light radiation. According to quantum mechanics, a high velocity electron will become wave like, having a wavelength that is inversely proportional to its velocity. When accelerated across large voltages, electrons can be made to have wavelengths on order of 0.003nm. High magnifications and resolving powers of these microscopes are consequences of shorter wavelengths of electron beam. The electron beam is focused and image is formed with magnetic lens. Both transmission & reflection beam modes of operation are possible.    

Electron Spectroscopy

Electron spectroscopy is an analytical technique to study the electronic structure and its dynamics in atoms and molecules. In general, an excitation source such as X-rays, electrons  or synchrotron radiation will eject an electron from an inner-shell orbital of an atom. Detecting photoelectrons that are ejected by X-rays is called X-ray Photoelectron Spectroscopy  (XPS) or electron spectroscopy for chemical analysis (ESCA). Detecting electrons that are ejected from higher orbitals to conserve energy during electron transitions is called Auger electron spectroscopy (AES).

Electron Spin Resonance (ESR)

The paramagnetic substances which contain unpaired electrons when subjected to a magnetic field, the energy levels corresponding to an electron will split up. When we apply an oscillating field in perpendicular direction whose frequency lies in microwave region then resonance occurs and electrons in lower energy state will absorb energy giving rise to absorption spectra. The spectrum is known as ESR.

Electron State

It is one of a set of discrete, quantized energies that are allowed for electrons. In the atomic case, each state is specified by four quantum numbers.

Electron Volt

The energy gained by electron when put under potential difference of 1 volt. It is equal to 1.6 x 10-19 J.


Branch of applied physics, which deals with devices made of semi-conductor materials having electrons/holes as charge carriers. The branch includes study and application of active/passive devices for various scientific and technology applications.


See electro deposition.


Chemical property which describes tendency of an atom to lose valance electrons.


It was the first electrical measuring instrument used to detect presence and magnitude of electric charge on a body.

Electrostatic Lens

Device used to focus electron beam.  

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