All articles A–Z

Electron density

Electron density is the probability per unit volume of finding an electron at a given point in space, a physical observable measured by X-ray diffraction.

Electron diffraction

Electron diffraction is the scattering of an electron beam by the periodic electric potential of a crystal, producing patterns from which atomic structure can be determined.

Electron donor–acceptor complex photoactivation

Electron donor–acceptor (EDA) complex photoactivation is a synthetic strategy where an electron-rich donor and electron-poor acceptor form a complex that absorbs visible light, generating radicals without a photocatalyst.

Electron electric dipole moment

The electron electric dipole moment (eEDM) is a hypothetical charge separation along the electron's spin axis; none has been observed, with the best limit set in 2023.

Electron electric dipole moment search

The electron electric dipole moment search (eEDM) looks for a permanent charge separation along the electron's spin; none has been found, with a current limit of 4.1×10⁻³⁰ e·cm.

Electron energy loss spectroscopy

Electron energy loss spectroscopy (EELS) measures the energy a beam of electrons transfers to a material, reading composition, bonding, and excitations, with modern instruments reaching single-atom sensitivity.

Electron energy-loss spectroscopy imaging

Electron energy-loss spectroscopy imaging is a transmission electron microscopy technique that maps elements and chemical bonding states pixel by pixel, and is especially useful for light elements such as nitrogen.

Electron energy-loss spectroscopy with monochromated STEM

Electron energy-loss spectroscopy with monochromated STEM (monochromated STEM-EELS) passes a scanning transmission electron microscope's beam through a monochromator, reaching few-meV energy resolution to measure bandgaps, plasmons, excitons, and vibrational modes.

Electron first-stage recovery program

Rocket Lab's Electron first-stage recovery program, begun in 2018, recovers the small-lift rocket's first stage by guided re-entry, parachutes, and retrieval at sea instead of propulsive landing.

Electron gun

An electron gun is an electrode assembly that produces, accelerates, and focuses a directed beam of electrons for vacuum tubes, electron microscopes, welding, and lithography.

Electron hole

An electron hole is a quasiparticle representing a missing electron in a filled valence band, behaving as a mobile positive charge carrier with charge +e in semiconductors.

Electron holography

Electron holography is an electron-microscopy technique that reconstructs the phase of the electron wave passing through a specimen, quantitatively imaging electric and magnetic fields at nanometer resolution.

Electron Hong-Ou-Mandel interferometry

Electron Hong-Ou-Mandel interferometry, or electronic HOM interferometry, collides single electrons from independent sources on a beam splitter; indistinguishable fermions antibunch, giving a Pauli dip that measures wave-packet indistinguishability.

Electron hydrodynamics

Viscous electron flow is a regime of electrical conduction in which momentum-conserving electron collisions dominate, so charge flows like a viscous fluid described by hydrodynamic equations rather than Ohm's law.

Electron hydrodynamics in graphene

Electron hydrodynamics in graphene is a transport regime where electrons collide with each other and flow collectively like a viscous fluid rather than obeying Ohm's law.

Electron ionization

Electron ionization, also called electron impact ionization, is the process in which an electron collision ejects bound electrons from an atom or molecule, leaving a positive ion.

Sep 21, 2026

Electron Kebebew

Electron Kebebew is an American endocrine surgeon and scientist, Chief of General Surgery at Stanford since 2018 and previously inaugural chief of the National Cancer Institute's endocrine oncology branch.

Electron localization function

The electron localization function (ELF), introduced by Axel Becke and Kathrin Edgecombe in 1990, visualizes chemical bonds, lone pairs, and atomic shells from quantum chemical calculations.

Electron magnetic moment

The electron magnetic moment is the magnetic dipole moment of the electron, produced by its spin and electric charge and measured in units of the Bohr magneton.

Electron mass

The electron mass, also called the electron rest mass, is the mass of the electron, the lightest charged elementary particle, about 9.109 × 10⁻³¹ kg or 0.511 MeV in energy.

Electron microprobe analysis

Electron microprobe analysis, also called electron probe microanalysis, is an analytical technique that measures characteristic X-rays to determine element concentrations in solids at the micrometer scale.

Electron microscope

An electron microscope forms images with a beam of electrons instead of light, resolving detail far beyond optical microscopes; the first was built in 1931.

Oct 21, 2026

Electron Microscopy

Electron microscopy is a family of imaging techniques using electron beams instead of light to visualize fine structure, including TEM and SEM, pioneered by Ernst Ruska and Max Knoll in 1931.

Electron mobility

Electron mobility measures how quickly an electron drifts through a metal or semiconductor under an electric field; it is a common metric for judging the quality of transistor materials.

Electron neutrino

The electron neutrino (νe) is an electrically neutral elementary particle of the Standard Model, paired with the electron and produced in beta decay and solar fusion.

Electron nuclear double resonance spectroscopy

Electron nuclear double resonance (ENDOR) spectroscopy is a magnetic resonance technique that detects nuclear transitions through an EPR signal, measuring hyperfine interactions in radicals, metalloproteins, and semiconductor defects.

Electron paramagnetic resonance

Electron paramagnetic resonance (EPR), also known as electron spin resonance (ESR), is a spectroscopic technique that probes unpaired electrons in free radicals, transition metal complexes, and defects; it was discovered in 1944.

Electron paramagnetic resonance imaging

Electron paramagnetic resonance imaging (EPRI, also called EPR imaging or EPROI) is a biomedical imaging method that maps paramagnetic probes in tissue to measure oxygen and redox status.

Electron paramagnetic resonance oximetry

Electron paramagnetic resonance oximetry, or EPR oximetry, is a spectroscopic method that measures oxygen partial pressure in tissue from broadening of an added spin probe's EPR spectrum.