Related topics: quantum dots , atoms , journal science , laser , physical review letters
Electron
hideThe electron is a subatomic particle that carries a negative electric charge. It has no known substructure and is believed to be a point particle. An electron has a mass that is approximately 1836 times less than that of the proton. The intrinsic angular momentum (spin) of the electron is a half integer value of 1/2, which means that it is a fermion. The anti-particle of the electron is called the positron, which is identical to electron except that it carries electrical and other charges of the opposite sign. In collisions electrons and positrons annihilate, producing a pair (or more) of gamma ray photons. Electrons participate in gravitational, electromagnetic and weak interactions.
The concept of an indivisible amount of electric charge was theorized to explain the chemical properties of atoms, beginning in 1838 by British natural philosopher Richard Laming; the name electron was introduced for this charge in 1894 by Irish physicist George Johnstone Stoney. The electron was identified as a particle in 1897 by J. J. Thomson and his team of British physicists. Electrons are identical particles that belong to the first generation of the lepton particle family. Electrons have quantum mechanical properties of both a particle and a wave, so they can collide with other particles and be diffracted like light. Each electron occupies a quantum state that describes its random behavior upon measuring a physical parameter, such as its energy or spin orientation. Because an electron is a type of fermion, no two electrons can occupy the same quantum state; this property is known as the Pauli exclusion principle.
In many physical phenomena, such as electricity, magnetism, and thermal conductivity, electrons play an essential role. An electron generates a magnetic field while moving, and it is deflected by external magnetic fields. When an electron is accelerated, it can absorb or radiate energy in the form of photons. Electrons, together with atomic nuclei made of protons and neutrons, make up atoms. However, electrons contribute less than 0.06% to an atom's total mass. The attractive Coulomb force between an electron and a proton causes electrons to be bound into atoms. The exchange or sharing of the electrons between two or more atoms is the main cause of chemical bonding.
Electrons were created by the Big Bang, and they are lost in stellar nucleosynthesis processes. Electrons are produced by cosmic rays entering the atmosphere and are predicted to be created by Hawking radiation at the event horizon of a black hole. Radioactive isotopes can release an electron from an atomic nucleus as a result of negative beta decay. Laboratory instruments are capable of containing and observing individual electrons, while telescopes can detect electron plasma by its energy emission. Electrons have multiple applications, including welding, cathode ray tubes, electron microscopes, radiation therapy, lasers and particle accelerators.
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News tagged with electrons
Accelerators and Light Sources of Tomorrow (Part 2: Accelerating with Light)
Dec 22, 2009 |
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Accelerators are far from achieving the highest energies their builders aspire to, but size and cost may limit the kinds of facilities funding agencies can support. In the future, new kinds of machines will ...
More precise measurements of the W boson
Dec 21, 2009 |
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(PhysOrg.com) -- "The W boson is one of the very few major building blocks of matter," Dmitri Denisov tells PhysOrg.com. "It is a member of a family of particles that is the most fundamental in nature. The W boson is res ...
Hot Electrons Could Double Solar Cell Power Efficiency
Dec 18, 2009 |
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Scientists have experimentally verified a theory suggesting that hot electrons could double the output of solar cells. The researchers, from Boston College, have built solar cells that successfully use hot ...
Caltech scientists film photons with electrons
Dec 16, 2009 |
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(PhysOrg.com) -- Techniques recently invented by researchers at the California Institute of Technology -- which allow the real-time, real-space visualization of fleeting changes in the structure of nanoscale ...
Scientists discover mechanism behind superinsulation
Dec 14, 2009 |
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(PhysOrg.com) -- Scientists at the U.S. Department of Energy's Argonne National Laboratory have discovered the microscopic mechanism behind the phenomenon of superinsulation, the ability of certain materials ...
New structure could produce efficient semiconductor laser sources
Dec 14, 2009 |
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(PhysOrg.com) -- University of Wisconsin-Madison researchers have achieved a nanoscale laser structure they anticipate will produce semiconductor lasers in the next two years that are more than twice as efficient ...
Elusive 'hot' electrons captured in ultra-thin solar cells
Dec 11, 2009 |
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Boston College researchers have observed the "hot electron" effect in a solar cell for the first time and successfully harvested the elusive charges using ultra-thin solar cells, opening a potential avenue to improved solar ...
Spin polarization achieved in room temperature silicon
Nov 27, 2009 |
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(PhysOrg.com) -- A group in The Netherlands has achieved a first: injection of spin-polarized electrons in silicon at room temperature. This has previously been observed only at extremely low temperatures, ...
The e-waste dilemma
Nov 24, 2009 |
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(PhysOrg.com) -- Electronic devices could create significant environmental and health problems after they are thrown away. UC Irvine researchers are working with engineers, manufacturers and public health ...
A Tiny Cage of Gold Responds to Light, Opening to Empty Its Contents
Nanotechnology / Bio & Medicine
Nov 19, 2009 |
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(PhysOrg.com) -- Researchers at Washington University in St. Louis have developed a polymer-coated gold nanocage that not only opens in response to light to release a small amount of a drug payload, but then closes when the ...
Crashing the size barrier
Nov 18, 2009 |
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Like surfers on monster waves, electrons can ride waves of plasma to very high energies in a very short distance. Scientists have proven that plasma acceleration works. Now they're developing it as a way to ...
Measuring Electron Orbitals
Nov 16, 2009 |
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(PhysOrg.com) -- For the first time, it has been possible to measure electron density in individual molecular states using what is known as the photoelectric effect. Now published in Science, this method repres ...
Argonne 'homegrown' hybrid solar cell aims for low-cost power
Nanotechnology / Nanomaterials
Nov 10, 2009 |
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(PhysOrg.com) -- Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have refined a technique to manufacture solar cells by creating tubes of semiconducting material and then "growing" ...
Sculptured materials allow multiple channel plasmonic sensors
Nov 10, 2009 |
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(PhysOrg.com) -- Sensors, communications devices and imaging equipment that use a prism and a special form of light -- a surface plasmon-polariton -- may incorporate multiple channels or redundant applications if manufacturers ...
Plasma-in-a-bag for sterilizing devices
Nov 09, 2009 |
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The practice of sterilizing medical tools and devices helped revolutionize health care in the 19th century because it dramatically reduced infections associated with surgery. Through the years, numerous ways of sterilization ...
