electronn.²

Brit.

/ᵻˈlɛktrɒn/, U.S.

/əˈlɛkˌtrɑn/,

/iˈlɛkˌtrɑn/

Origin: Formed within English, by compounding. Etymons: electric adj., ion n.

Etymology: < electr- (in electric adj.; compare electro- comb. form) + -on (in ion n.; compare -on suffix¹).

1. A subatomic particle which has a negative electric charge equal in magnitude to the positive charge of the proton, is a constituent of all atoms, and is the principal carrier of electric current in solids. Also (occasionally): the positive analogue or antiparticle of this (now called positron).Originally (quot. 1891), the name electron was proposed for the electric charge associated with a univalent ion. Subsequently the name was given to the ‘corpuscles’ (corpuscle n. 2c) discovered in 1897 by J. J. Thomson in cathode rays, and carrying a negative charge of this magnitude. When the positron was discovered in 1933, its discoverer proposed negatron as a name for the electron (see negatron n. 2, and cf. earlier negaton n.), but that term gained little currency.The mass of the electron is about 9 × 10⁻²⁸ gram, ¹/ ₁₈₃₆ that of the proton. Electrons orbit the positively charged nuclei of atoms and are responsible for binding atoms together in molecules, as well as for the electrical, thermal, optical, and magnetic properties of solids. In the modern classification of particles the electron is classed as a lepton.positive electron: see positive electron n. at positive adj. and n. Compounds.

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the world > matter > chemistry > atomic chemistry > [noun] > electrons

electron1891

isostere1919

the world > matter > physics > electromagnetic radiation > electronics > electronic phenomena > [noun] > electron

electron1891

corpuscle1897

the world > matter > physics > atomic physics > particle physics > particle avoiding strong interaction > electron > [noun]

electron1891

E1894

1891 G. J. Stoney in Trans. Royal Dublin Soc. 4 583 A charge of this amount is associated in the chemical atom with each bond...These charges, which it will be convenient to call electrons, cannot be removed from the atom; but they become disguised when atoms chemically unite.

1897 J. Larmor in Proc. Royal Soc. 63 365 To obtain a definite and consistent theoretical basis it was necessary to contemplate the material system as made up of discrete molecules, involving in their constitutions orbital systems of electrons.

1907 Westm. Gaz. 19 Feb. 2/1 When the atom is considered together with its electric charge it is called an ‘ion’, while the charge, considered in itself, is the ‘electron’.

1908 J. Davidson Testament 102 Repeating, in the microcosm, Electron, atom, system, universe.

1922 T. M. Lowry Inorg. Chem. xxxi. 550 Fluorine, with atomic number 9, very readily takes up an additional electron in order to complete the octet and enters into combination as a univalent anion, F⁻.

1930 ‘J. Taine’ Iron Star xvii. 289 Only the faint, flickering glow from the geyser of electrons lit the mounded crater with a dead light.

1947 ‘H. MacDiarmid’ Compl. Poems (1994) II. 1339 I am full Of the violent energy of the minute electron In the enormous atom.

1954 A. J. Ayer Philos. Ess. i. 9 Whether, for example, we are to treat such objects as electrons as being directly accessible to observation, or only such common-sense objects as chairs and tables.

1968 M. S. Livingston Particle Physics iv. 62 This has the effect of producing, out of energy, a pair of electrons, one with negative and one with positive charge.

1981 P. Davies Edge of Infinity (1983) ii. 42 The simplest atom is that of the element hydrogen , which consists of a single proton orbited by a single electron.

1998 BBC Vegetarian Good Food Sept. 47/1 Free radicals..damage other molecules by stealing electrons to repair themselves.

2. figurative.

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1904 Sat. Rev. 30 Jan. 138/1 Mr. Hardy's puppets are infinitesimal—mere ‘electrons’, shifted hither and thither, for no reason, by some impalpable agency.

1913 Empire Rev. Dec. 1336 The imponderable electrons of sentiment and feeling which allow our far-away peoples and clans to cohere.

1929 D. H. Lawrence Pansies 26 The swan within vast chaos, within the electron.

1997 S. Armitage CloudCuckooLand 81 Region of the silver-plated sturgeon, region of the loose electron of the ermine.

Compounds

C1. General attributive.

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1899 Proc. Physical Soc. 17 643 Attention may be drawn in conclusion to several papers by P. Drude ‘On the Electron-theory of Metals’.

1903 Science 26 June 1001/2 The electron theory..explains Ampère's idea that magnetism is due to a rotating current of electricity round each atom of iron.

1921 Discovery Sept. 226/2 The corresponding electron velocities are so small that it is difficult to measure them.

1926 Atlantic Monthly Apr. 377/2 The study of electron-emission has given us..radio broadcasting.

1938 R. W. Lawson tr. G. von Hevesy & F. A. Paneth Man. Radioactivity (ed. 2) iv. 90 The energy levels of atoms as established by experiments on electron collisions.

1967 New Scientist 21 Dec. 707/2 To understand the electron-transfer process in detail has proved to be a stiff test for the theoreticians.

1987 Physics Rep. 146 319 In a simple picture, the Auger effect may be regarded as electron transitions between atomic orbitals.

1995 T. Hughes New Sel. Poems 278 Their brains budded Clone replicas of the electron world.

2000 H. D. Huskey in R. Rojas & U. Hashagen First Computers i. 85 Control of electron flow between the source and drain depended upon the field established by the gate terminal.

C2.

electron acceptor n. Chemistry an atom, molecule, etc., which can receive electrons from an electron donor.

ΚΠ

1923 Chem. Abstr. 17 1382 The excess adsorbed Ag ions act as electron acceptors which are more active than the normal Ag ions of the lattice surface.

1988 J. D. Barrow & F. J. Tipler Anthropic Cosmol. Princ. (rev. ed.) viii. 543 In these hydrides hydrogen acts as an electron acceptor.

2004 Science 9 Apr. 167/1 The fullerene C₆₀ is a good electron acceptor, and fullerides can be formed by doping C₆₀ crystals with alkali metals.

electron affinity n. Chemistry the quantity of energy released when a neutral atom of a given element combines with an electron to form a negative ion; (hence) a measure of an element's tendency to act as an oxidizing agent.

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1912 Chem. Abstr. 6 2709 With increasing electron affinity this change in the spectrum was more and more masked by the gradual extinction of the total emission.

1958 Proc. Royal Soc. A. 247 344 The values of electron affinity obtained from the pair-production process in carbon monoxide yield values compatible with the photo-detachment value.

1994 D. F. Shriver et al. Inorg. Chem. (ed. 2) i. 42 Elements close to fluorine..can be expected to have the highest electron affinities.

electron beam n. Science a beam or stream of electrons, usually artificially generated; a cathode-ray beam.

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1922 Proc. Physical Soc. 35 127 The method of focusing..employs positive ions derived from the residual gas..to neutralise the spreading of the electron beam.

1956 Nature 3 Mar. 419/2 A series of remarkable electron micrographs..obtained by..using a new fine electron-beam technique.

2001 J. C. Grimwood Pashazade (2003) xli. 272 On the other side of the screen to Hani an electron beam rastered down the glass and Hani swore.

electron camera n. a camera employing electron beams; spec. a television camera that converts an optical image directly into an electrical signal.

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1930 G. P. Thomson & C. G. Fraser in Proc. Royal Soc. A. 128 641 The apparatus described in this paper, which will be called for shortness an electron camera, is intended to study the diffraction patterns formed by the reflection of cathode rays from crystalline surfaces.

1937 Discovery Nov. 329/1 The electron camera at the transmitter, with a cathode-ray tube at the receiving end.

1999 Jrnl. Nucl. Med. 40 868/1 This ‘electron camera’ is a serious rival to existing autoradiographic techniques.

electron cloud n. Physics the electrons surrounding the nucleus of an atom, viewed as a cloud-like mass.

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1920 Proc. Physical Soc. 33 114 The change in the distribution of the electron cloud which must occur when the voltage was applied might be responsible.

1946 Nature 16 Nov. 717/1 In the absence of a magnetic field, the electron-cloud in the outer incomplete shells of the atom or the molecule react [sic] on the nucleus.

2002 U.S. News & World Rep. 9 Sept. 68/2 Friction requires movement, but stationary atoms can also cling together briefly as the random shifting of their electron clouds grant each a transient electric charge.

electron-deficient adj. Chemistry having fewer electrons than normal; spec. containing a chemical bond in which a pair of electrons is shared between more than two atoms.

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1939 Jrnl. Amer. Chem. Soc. 61 1597/2 It is suggested that the common factor in these reactions is the electron-deficient nature of the catalyst.

1955 Q. Rev. Chem. Soc. 9 176 The boron hydrides and some of their derivatives are examples of electron-deficient compounds.

1995 D. M. P. Mingos Essent. Inorg. Chem. 1 (1997) 30 An electron deficient molecule has fewer valence electrons involved in covalent bonds than the number of orbitals available.

2002 New Scientist 2 Feb. 21/2 On the opposite side, they placed an electron ‘collector’ doped with electron-deficient impurities. These have lots of missing electrons, effectively creating positive ‘holes’.

electron-dense adj. Biology and Medicine (chiefly with reference to electron microscopy) opaque to the passage of electrons.

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1951 Biochimica et Biophysica Acta 7 179 Further washing of cell walls from Strep. faecalis with distilled water on the high speed centrifuge resulted in the removal of residual electron-dense cytoplasmic material.

1987 J. V. Priestley in A. J. Turner & H. S. Bachelard Neurochem. iii. 85 The oxidized..product..chelates with OsO₄ to form a highly electron-dense product.

1995 C. Nielsen Animal Evol. xvii. 128 The microvilli often terminate in a small knob and there is in many cases an electron-dense epicuticle at the surface.

electron density n. the number of electrons per unit volume; (Chemistry) the quantum-mechanical probability that an electron will be found at a given point in an atom, molecule, etc.

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1908 Jrnl. Amer. Chem. Soc. 30 1726 Müller also recognizes that his view does not show in any way how the different electrolytes affect the electron density.

1939 L. Pauling Nature Chem. Bond i. 29 The electron distribution function for a poly-electronic atom or ion shows the presence of electron shells as regions of maximum electron density.

1972 Jrnl. Brit. Astron. Assoc. 82 306 Assuming that the coronal electron densities were those given by the model due to Blaumbach and Allen,..the radial velocity components of the emissive regions were calculated.

1995 D. M. P. Mingos Essent. Inorg. Chem. 1 (1997) 17 The π-bonds have a nodal plane, i.e. a region of zero electron density in the plane containing the atoms.

electron diffraction n. Science the diffraction of a beam of electrons; frequently attributive.

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1927 Physical Rev. Dec. 705 The spacing factor concerned in electron diffraction by a nickel crystal.

1939 Nature 25 Feb. 372/2 Details of their Finch electron diffraction camera intended for industrial research.

1958 Jrnl. Iron & Steel Inst. 189 56/2 The marked thinness of the blades and prisms..resulted in electron diffraction patterns being observed.

1978 G. C. Hill & J. S. Holman Chem. in Context viii. 101 The presence of dimerized pairs of carboxylic acid molecules in benzene has been confirmed by electron diffraction measurements.

2001 R. W. Cahn Coming of Materials Sci. vi. 246 The important techniques of characterising surfaces, such as low-energy electron diffraction, have only been skirted.

electron donor n. Chemistry an atom, molecule, etc., which can donate electrons to an electron acceptor.

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1929 Jrnl. Physical Chem. 33 261 In point of fact, a direct photomechanical action of radiation upon matter has been..more specifically worked out by F. Weigert for paired systems (atoms or atom groups) of electron donors and electron acceptors.

1978 G. C. Hill & J. S. Holman Chem. in Context xiii. 186 The oxidizing agent (oxidant) is the electron acceptor and the reducing agent (reductant) is the electron donor.

2005 C. de Duve Singularities v. 51 The so-called heterotrophic theory of the origin of life..implies that some of these products of cosmic and prebiotic Earth chemistry acted as the first electron donors,..and that the electrons were caught by some mineral acceptors.

electron gas n. Science a system of electrons, typically within a solid, which is unconstrained by individual atoms or molecules and can be approximately described using the kinetic theory of gases.

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the world > matter > physics > atomic physics > particle physics > particle avoiding strong interaction > electron > [noun] > space filled with particles

electron gas1913

sea1955

1913 W. H. Keesom in Proc. Section Sci. Koninklijke Akad. van Wetenschappen te Amsterdam 16 236 The frequencies in an electron gas with the same order of magnitude of the number of particles per unit of volume, become very much higher than in the ordinary material gases.

1962 Listener 10 May 809/2 A few free electrons, drifting about hither and thither and forming an electron-gas in the metal.

2001 O. Sacks Uncle Tungsten xxiv. 303 It was also wondered..what might happen to the ‘electron gas’ in metals if they were cooled to temperatures near absolute zero.

electron gun n. Science a device in which electrons obtained by thermionic emission from a heated cathode are emitted as a narrow beam.

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the world > matter > physics > atomic physics > particle physics > particle avoiding strong interaction > electron > [noun] > device emitting beams

electron gun1924

gun1933

undulator1951

1924 Brass World Feb. 52/1 The electron gun is not swung about, but its stream of projectiles is deflected by means of electric or magnetic forces.

1930 Chem. Abstr. 2044 The electron gun..consists of a hot filament near the small hole in a diaphragm and on the axis of a hollow cylinder at a pos. potential, which produces a ‘visible’ beam of electrons.

1953 S. W. Amos & D. C. Birkinshaw Television Engin. I. iv. 52 The electron gun is an electrode assembly designed to produce a narrow beam of electrons.

1991 Engineering July–Aug. 40/1 Ingress of metal vapour into the electron gun during welding can cause high voltage breakage between gun electrodes.

2005 Sci. Amer. (U.K. ed.) June 82/1 I replaced my electron-gun boob tube with a 42-inch plasma flat panel.

electron lens n. Physics a device for modifying an electron beam in the same way as an ordinary lens modifies a light beam.

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1931 Physical Rev. 1 Aug. 585 (heading) Electron lenses.

1949 Proc. Royal Soc. A. 197 456 An electron gun, combined with a suitable aperture and electron lens system, produces a coherent illuminating beam.

1999 D. Mitchell Ghostwritten 389 EyeSat 46SC was designed to track hurricanes from the Caribbean to the States on the Gulf of Mexico. It was later modified to combat drug trafficking, and fitted with the most powerful terrestrial-facing electronlens ever sent into space.

electron-lucent adj. Biology and Medicine (chiefly with reference to electron microscopy) transparent to electrons.

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1953 Jrnl. Exper. Med. 98 610 The cytoplasmic matrix is essentially electron-lucent except for variable concentrations of granules.

1995 C. Nielsen Animal Evol. xxxviii. 294 The ectoderm is monolayered and covered by a chitinous cuticle,..with an electron-dense outer and a homogeneous, electron-lucent inner zone.

electron microgram n. = electron micrograph n.

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1943 Jrnl. Amer. Med. Assoc. 16 Oct. 400/2 Figure 1 shows an electronmicrogram (1 × 14,500) of a sample of purified SK murine virus.

2005 Colloids & Surfaces B. 46 138 (caption) Scanning electron microgram (SEM) of calcium lactate pentahydrate and its anhydrate.

electron micrograph n. a micrograph produced by an electron microscope.

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1934 Sci. Abstr. A. 37 203 The electron micrographs, taken with a kathode temperature of 1000° C., showed the crystalline surface structure of the nickel.

1946 A. Nelson Princ. Agric. Bot. xxiv. Plate 100 (caption) Electron micrograph of a dried film of purified tobacco mosaic virus.

1992 D. V. Parums in C. E. Lewis & J. O'D. McGee Macrophage ix. 371 (caption) A transmission electron micrograph showing a vasa vasorum in the aortic adventitia of a patient with advanced atherosclerosis.

electron micrographic adj. relating to or obtained by electron micrography.

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1944 Jrnl. Biol. Chem. 156 598 The difference probably was related to the measurement of the images irrespective of orientation on the electron micrographic plates.

1998 Proc. National Acad. Sci. U.S.A. 95 6236/2 The electron micrographic evidence for paracrystallinity of the protein filaments from silica spicules of another sponge.

electron micrography n. the making and interpretation of electron micrographs.

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1941 Amer. Jrnl. Pathol. 17 576 (heading) The electron micrography of purified viruses.

1968 C. W. Schwabe & A. Kilejian in M. Florkin & B. T. Scheer Chem. Zool. II. iii. vi. 472 By electron micrography, several workers..have shown that the integument of some adult and larval tapeworms is covered with minute ‘villi’.

2006 Jrnl. Colloid & Interface Sci. 304 1 Characterization of these particles was carried out using transmission electron micrography (TEM), and vibrating sample magnetometry (VSM).

electron microprobe n. a device for focusing a narrow beam of electrons on to a minute area of a sample, exciting phenomena (esp. X-ray fluorescence) which can be analysed to yield chemical or structural information; a microanalytical instrument incorporating such a probe; cf. microanalyser n.; frequently attributive.

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1959 Endeavour Apr. 86/1 Perhaps the most important development of X-ray spectroscopy during the last few years is that using the various electron microprobe techniques originating in work by R. Castaing.

1961 Science 8 Dec. 1938/2 The degree of destructiveness of the electron microprobe is not yet established, but..I believe conventional mass spectroscopy cannot hope to match it in nondestructiveness.

1977 A. Hallam Planet Earth 17/1 Tiny crystals that can be analysed only by use of a special instrument, the electron microprobe.

2001 Powder Diffraction 16 92 Electron microprobe analysis confirmed K:Pb:S as 2:1:2 for the annealed palmierite powder.

electron multiplier n. Electronics an instrument for amplifying the intensity of a small current of electrons, typically by means of secondary emission at each of a succession of electrodes; cf. multiplier n. 4.

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1934 Electronics 7 242 An electron multiplier. A new type of cold-cathode tube of high current amplifying ability marks another step toward the solution of television problems.

1953 S. W. Amos & D. C. Birkinshaw Television Engin. I. v. 107 If the return beam is directed into an electron multiplier the tube output can be increased.

2007 Radiation Physics & Chem. 76 384/1 They replaced the electrostatic analyzer with a rotatable channel electron multiplier.

electron neutrino n. Particle Physics a type or flavour (flavour n. 5) of neutrino associated with reactions involving electrons (one of the three known types of neutrino); cf. muon neutrino n. at muon n. Compounds, tau neutrino n. at tau n. Compounds 3.

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1959 Žurnal Eksperimental′noj i Teoretičeskoj Fiziki 37 1751 (title) Electron and muon neutrinos.

1993 Guardian 26 Aug. ii. 17/4 Natural radioactivity and fusion in the sun produce electron-neutrinos; experiments at accelerators and cosmic rays show that there are also two other varieties in nature, known as the muon-neutrino and tau-neutrino.

2003 Astroparticle Physics 20 197/1 RICE was originally conceived as an experiment to search for electron neutrinos.

electron optics n. [in sense (a) after German Elektronenoptik (A. Heydeweiller 1915, in Verhandl. der Deutsch. Physikalischen Ges. 17 359); in sense (b) after German Elektronenoptik (Knoll & Ruska 1932, in Ann. der Physik 12 607)] Physics (a) optical properties as ascertained from or related to electronic properties (rare, now disused); (b) a branch of physics concerned with the influence of electric and magnetic fields on the movement of electrons.

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1916 Chem. Abstr. 10 299 The number of these latter electrons is not definitely known, but is almost surely greater than 1, from considerations of the electron-optics of the H-cation in H₂O.

1932 Sci. Abstr. A. 35 645 Application of geometric electron optics makes it possible to explain the behaviour of the beam in an electron tube.

1969 Times 28 Mar. 25/3 The British company claims to have gained the lead, with some Government financial aid, through its expertise in precision and electron optics.

1990 Proc. Royal Microsc. Soc. 25 339/3 (advt.) Optimum conditions for a contamination-free specimen environment and maximum cleanliness of the electron optics.

2007 Ultramicroscopy 107 174/1 One can presuppose that the magnitude of lens errors in electron optics is very small.

electron-optical adj. Physics of or relating to electron optics; employing or involving electron optics.

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1933 Sci. Abstr. A. 36 199 A combined electric and magnetic deflection method which gives electron-optical enlargements of emitting surfaces.

1951 Engineering 13 July 40/2 A tube with sufficiently good electron-optical focus for high-definition pictures was made.

1977 Jrnl. Royal Soc. Arts 125 772/2 Direct linear measurement of pulse durations by electronoptical streak-cameras.

2007 Ultramicroscopy 107 106 An electron-optical effect caused by specimen charging.

electron pair n. Chemistry and Physics a linked or interacting pair of electrons; spec. (a) two electrons with opposite spins occupying the same orbital in an atom or molecule; cf. duplet n. 2; (b) an electron and a positron formed by decay of a gamma-ray photon; cf. pair production n. at pair n.¹ Compounds 1.

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1910 London, Edinb., & Dublin Philos. Mag. 6th Ser. 19 1 The special electron pair consists of a positive electron which acts as though uniformly distributed through a sphere of radius R = 0.795 x 10^-8... The negative electron is situated at distance r along the electric axis of the atom from the centre of the sphere of radius R.

1923 G. N. Lewis Valence vi. 83 We may suppose that the normal state of the hydrogen molecule is one in which the electron pair is symmetrically placed between the two atoms.

1933 R. A. Millikan in Science 25 Aug. 154/2 A free positive and negative electron-pair often result from the collision of a sufficiently energetic photon with an atomic nucleus.

1958 O. R. Frisch Nucl. Handbk. viii. 12 Electron pairs can be created by other processes including: (a) Passage of a heavy particle through matter..(b) Passage of a fast electron through the field of a nucleus..(c) Collision between two electrons.

1964 J. W. Linnett Electronic Struct. Molecules ii. 28 This difficulty of solving the Schrödinger equation for systems containing two or more electrons means that the development of the electron-pair bond has to be based, to a large extent, on empirical reasoning.

1995 D. M. P. Mingos Essent. Inorg. Chem. 1 (1997) 8 Classically the bond order is the number of electron pairs being shared between connected atoms.

electron probe n. = electron microprobe n.

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1943 Science 17 Dec. 10/1 In the electron microanalyzer a very small area of the specimen is irradiated with an electron probe, a stream of these particles of electricity brought into a beam by a two-stage magnetic lens system.

1972 R. Galopin & N. F. M. Henry Microsc. Study Opaque Minerals i. 6/1 The modern micro-beam electron probe is the almost perfect instrument in the chemical study of fine-grained materials.

1989 Brit. Archaeol. May–June 28/2 A fragment of the plate has now been examined..using modern metallography and electron probe microanalysis.

electron spin n. Particle Physics the intrinsic angular momentum of an electron, denoted by the quantum number s; the property of an electron by virtue of which it possesses this momentum.

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1926 Nature 20 Feb. 264/2 The dotted lines represent the position of the energy levels to be expected in the absence of the spin of the electron.]

1926 Proc. National Acad. Sci. U.S.A. 12 452 There seems to be no reason a priori why the magneto-magnetical ratio for the electron spin should be even of the same order of magnitude as for an electron revolving in an orbit.

1935 A. Farkas Orthohydrogen, Parahydrogen & Heavy Hydrogen ii. 4 The distinction between the hydrogen modifications is based on the different orientations of the nuclear spins, while in the case of helium it depends on the orientation of the electron spins.

1992 D. G. Campbell Crystal Desert x. 197 Magnetite is a mixture of ferric and ferrous iron, which have opposite electron spins and therefore create a miniature magnetic dipole.

electron spin resonance n. Physics and Chemistry resonance (sense 5c) in which the transition involved is that of electrons between states of different spin, esp. unpaired bound electrons in a paramagnetic ion; abbreviated ESR.

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the world > matter > physics > quantum theory > electron spin > [noun] > electron spin resonance

electron spin resonance1952

ESR1955

the world > matter > physics > atomic physics > decomposition of light, spectrum > study of spectra > types of spectrometry or spectroscopy > [noun] > electron spin resonance spectroscopy

electron spin resonance1952

ESR1955

1952 Physical Rev. 15 Nov. 951/1 We have observed conduction electron spin resonance absorption in fine particles of metallic sodium..at a frequency of 9240 Mc/sec.

1972 R. A. Jackson Mechanism iv. 61 Electron spin resonance spectroscopy, which is very sensitive and will detect radical concentrations down to about 10⁻⁹ m, is extremely useful.

2003 B. Bryson Short Hist. Nearly Everything (2004) x. 199 Scientists devised other methods of dating ancient materials, among them..electron spin resonance, which involves bombarding a sample with electromagnetic waves and measuring the vibrations of the electrons.

electron telescope n. Astronomy a telescope that detects incident electrons or electrons generated by incident light.Early kinds used the principle of a photoelectric detector; later ones that of a scintillation counter.

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1937 Technol. Trends & National Policy (U.S. National Resources Comm.: Subcomm. on Technol.) i. iii. 29 Particularly promising and perhaps some day needing legislative enforcement, are the uses of infrared light, with the electron telescope, for sighting through fog the sun, the signal lights and hot funnels of an approaching ship.

1948 Jrnl. Brit. Interplanetary Soc. Nov. 250 The ‘electron telescope’ has been used to make visible stars which could not otherwise be detected.

2007 Planetary & Space Sci. 55 2/1 The Kiel Electron Telescope (KET) is designed to measure electron intensities for energies above 2.5 MeV.

electron tube n. a vacuum tube containing two or more electrodes, such that a current can flow in a controlled way between them; spec. a thermionic valve (= tube n. 2g(b)); (also) a gas-filled tube in which an electric discharge takes place.For the spec. sense, valve is the usual term in British English, and tube in American English.

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the world > matter > physics > electromagnetic radiation > electronics > electronic devices or components > thermionic valve > [noun] > vacuum tube or thermionic valve

vacuum tube1859

trigger tube1894

audion1906

pliotron1915

diode1919

electron tube1919

negatron1919

pentode1919

power valve1919

tetrode1919

triode valve1919

magnetron1921

bright emitter1923

peanut valve1923

peanut1924

power tube1924

multiple valve1929

thyratron1929

heptode1932

hexode1933

pentagrid1933

acorn tube1934

octode1934

triode-pentode1936

triode-hexode1937

transitron1939

trochotron1947

steering diode1957

1919 Science 21 Nov. 478/1 ‘Theory of action of electron tubes as amplifiers,’ John M. Miller, Bureau of Standards.

1930 Electronics Apr. 25/2 The electron-tube control of the stage lighting in the..Chicago Civic Opera House.

1964 L. H. Van Vlack Elements Materials Sci. (ed. 2) 409 (Gloss.) Transistor , an electrical device utilizing semiconductors and performing some of the functions of electron tubes.

1996 E. Sridharan Polit. Econ. Industr. Promotion ii. 28 Electron tubes can be of many types, the best known being the TV picture tube.

electron wave n. Physics the wave associated with the movement of an electron and held to account for its wave-like properties; a de Broglie wave of an electron.

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1927 Proc. National Acad. Sci. U.S.A. 13 460 A single plane of atoms reflects a very appreciable fraction of the electron wave, whereas the same plane would reflect only an inappreciable part of an X-ray wave.

1958 E. U. Condon & H. Odishaw Handbk. Physics viii. vi. 77/2 The small periodic deviations of the emission current..come about through the interference effect of electron waves.

2007 Radiation Physics & Chem. 76 213/2 Thin objects, that consist mainly of light atoms (H, C, N, O, S, etc.), are basically transparent to the incident electron wave.

This entry has been updated (OED Third Edition, June 2008; most recently modified version published online March 2022).

单词	electron
释义	electronn.¹ Brit. /ᵻˈlɛktrɒn/, U.S. /əˈlɛkˌtrɑn/, /iˈlɛkˌtrɑn/ Origin: A borrowing from Greek. Etymon: Greek ἤλεκτρον. Etymology: < ancient Greek ἤλεκτρον (see electrum n.). Compare electre n. 1. An alloy of gold and silver; = electrum n. 2. ΘΚΠ society > occupation and work > materials > derived or manufactured material > metal > alloy > [noun] > alloy of precious metals > alloy of gold and silver electrec1384 electruma1398 pewtera1425 amber1572 green gold1697 electron1856 1856 G. Grote Hist. Greece XII. ii. xcviii. 659 Precious metals (gold, silver, and electron). 1877 W. Jones Finger-ring Lore 459 Mediæval ring..formed of electron, or gold much alloyed with silver. 1906 Bull. Metrop. Mus. Art 1 122/2 A pair of spirals of pale gold or electron (a natural alloy of gold and silver). 1953 Proc. Amer. Philos. Soc. 97 217/2 The excavators were lucky enough to hit upon the tombs of local princes, full of precious objects made of gold, silver, electron, iron, amber etc. 2001 Dumbarton Oaks Papers 55 209 The trikephala or trikephala prattomena could, in theory, designate both electron or silver coins and gold coins. 2. Amber; = electrum n. 1a. rare. ΘΚΠ society > occupation and work > materials > raw material > gem or precious stone > amber > [noun] amber1365 electruma1398 lambera1400 karabe1545 electre1595 succin1596 ounce stone1601 succinum1608 bead-amber1611 sunstone1848 succinite1854 electron1882 burmite1893 1882 R. Jefferies Bevis III. xiii. 197 How long from the first rubbing of electron or amber, and a leaping up of little particles to it, to the electric tramway? 1938 Sci. Monthly June 517/1 It is evident how long a distance has been travelled from rubbing cat's fur on amber (electron). This entry has been updated (OED Third Edition, June 2008; most recently modified version published online March 2022). electronn.² Brit. /ᵻˈlɛktrɒn/, U.S. /əˈlɛkˌtrɑn/, /iˈlɛkˌtrɑn/ Origin: Formed within English, by compounding. Etymons: electric adj., ion n. Etymology: < electr- (in electric adj.; compare electro- comb. form) + -on (in ion n.; compare -on suffix¹). 1. A subatomic particle which has a negative electric charge equal in magnitude to the positive charge of the proton, is a constituent of all atoms, and is the principal carrier of electric current in solids. Also (occasionally): the positive analogue or antiparticle of this (now called positron).Originally (quot. 1891), the name electron was proposed for the electric charge associated with a univalent ion. Subsequently the name was given to the ‘corpuscles’ (corpuscle n. 2c) discovered in 1897 by J. J. Thomson in cathode rays, and carrying a negative charge of this magnitude. When the positron was discovered in 1933, its discoverer proposed negatron as a name for the electron (see negatron n. 2, and cf. earlier negaton n.), but that term gained little currency.The mass of the electron is about 9 × 10⁻²⁸ gram, ¹/ ₁₈₃₆ that of the proton. Electrons orbit the positively charged nuclei of atoms and are responsible for binding atoms together in molecules, as well as for the electrical, thermal, optical, and magnetic properties of solids. In the modern classification of particles the electron is classed as a lepton.positive electron: see positive electron n. at positive adj. and n. Compounds. ΘΚΠ the world > matter > chemistry > atomic chemistry > [noun] > electrons electron1891 isostere1919 the world > matter > physics > electromagnetic radiation > electronics > electronic phenomena > [noun] > electron electron1891 corpuscle1897 the world > matter > physics > atomic physics > particle physics > particle avoiding strong interaction > electron > [noun] electron1891 E1894 1891 G. J. Stoney in Trans. Royal Dublin Soc. 4 583 A charge of this amount is associated in the chemical atom with each bond...These charges, which it will be convenient to call electrons, cannot be removed from the atom; but they become disguised when atoms chemically unite. 1897 J. Larmor in Proc. Royal Soc. 63 365 To obtain a definite and consistent theoretical basis it was necessary to contemplate the material system as made up of discrete molecules, involving in their constitutions orbital systems of electrons. 1907 Westm. Gaz. 19 Feb. 2/1 When the atom is considered together with its electric charge it is called an ‘ion’, while the charge, considered in itself, is the ‘electron’. 1908 J. Davidson Testament 102 Repeating, in the microcosm, Electron, atom, system, universe. 1922 T. M. Lowry Inorg. Chem. xxxi. 550 Fluorine, with atomic number 9, very readily takes up an additional electron in order to complete the octet and enters into combination as a univalent anion, F⁻. 1930 ‘J. Taine’ Iron Star xvii. 289 Only the faint, flickering glow from the geyser of electrons lit the mounded crater with a dead light. 1947 ‘H. MacDiarmid’ Compl. Poems (1994) II. 1339 I am full Of the violent energy of the minute electron In the enormous atom. 1954 A. J. Ayer Philos. Ess. i. 9 Whether, for example, we are to treat such objects as electrons as being directly accessible to observation, or only such common-sense objects as chairs and tables. 1968 M. S. Livingston Particle Physics iv. 62 This has the effect of producing, out of energy, a pair of electrons, one with negative and one with positive charge. 1981 P. Davies Edge of Infinity (1983) ii. 42 The simplest atom is that of the element hydrogen , which consists of a single proton orbited by a single electron. 1998 BBC Vegetarian Good Food Sept. 47/1 Free radicals..damage other molecules by stealing electrons to repair themselves. 2. figurative. ΚΠ 1904 Sat. Rev. 30 Jan. 138/1 Mr. Hardy's puppets are infinitesimal—mere ‘electrons’, shifted hither and thither, for no reason, by some impalpable agency. 1913 Empire Rev. Dec. 1336 The imponderable electrons of sentiment and feeling which allow our far-away peoples and clans to cohere. 1929 D. H. Lawrence Pansies 26 The swan within vast chaos, within the electron. 1997 S. Armitage CloudCuckooLand 81 Region of the silver-plated sturgeon, region of the loose electron of the ermine. Compounds C1. General attributive. ΚΠ 1899 Proc. Physical Soc. 17 643 Attention may be drawn in conclusion to several papers by P. Drude ‘On the Electron-theory of Metals’. 1903 Science 26 June 1001/2 The electron theory..explains Ampère's idea that magnetism is due to a rotating current of electricity round each atom of iron. 1921 Discovery Sept. 226/2 The corresponding electron velocities are so small that it is difficult to measure them. 1926 Atlantic Monthly Apr. 377/2 The study of electron-emission has given us..radio broadcasting. 1938 R. W. Lawson tr. G. von Hevesy & F. A. Paneth Man. Radioactivity (ed. 2) iv. 90 The energy levels of atoms as established by experiments on electron collisions. 1967 New Scientist 21 Dec. 707/2 To understand the electron-transfer process in detail has proved to be a stiff test for the theoreticians. 1987 Physics Rep. 146 319 In a simple picture, the Auger effect may be regarded as electron transitions between atomic orbitals. 1995 T. Hughes New Sel. Poems 278 Their brains budded Clone replicas of the electron world. 2000 H. D. Huskey in R. Rojas & U. Hashagen First Computers i. 85 Control of electron flow between the source and drain depended upon the field established by the gate terminal. C2. electron acceptor n. Chemistry an atom, molecule, etc., which can receive electrons from an electron donor. ΚΠ 1923 Chem. Abstr. 17 1382 The excess adsorbed Ag ions act as electron acceptors which are more active than the normal Ag ions of the lattice surface. 1988 J. D. Barrow & F. J. Tipler Anthropic Cosmol. Princ. (rev. ed.) viii. 543 In these hydrides hydrogen acts as an electron acceptor. 2004 Science 9 Apr. 167/1 The fullerene C₆₀ is a good electron acceptor, and fullerides can be formed by doping C₆₀ crystals with alkali metals. electron affinity n. Chemistry the quantity of energy released when a neutral atom of a given element combines with an electron to form a negative ion; (hence) a measure of an element's tendency to act as an oxidizing agent. ΚΠ 1912 Chem. Abstr. 6 2709 With increasing electron affinity this change in the spectrum was more and more masked by the gradual extinction of the total emission. 1958 Proc. Royal Soc. A. 247 344 The values of electron affinity obtained from the pair-production process in carbon monoxide yield values compatible with the photo-detachment value. 1994 D. F. Shriver et al. Inorg. Chem. (ed. 2) i. 42 Elements close to fluorine..can be expected to have the highest electron affinities. electron beam n. Science a beam or stream of electrons, usually artificially generated; a cathode-ray beam. ΚΠ 1922 Proc. Physical Soc. 35 127 The method of focusing..employs positive ions derived from the residual gas..to neutralise the spreading of the electron beam. 1956 Nature 3 Mar. 419/2 A series of remarkable electron micrographs..obtained by..using a new fine electron-beam technique. 2001 J. C. Grimwood Pashazade (2003) xli. 272 On the other side of the screen to Hani an electron beam rastered down the glass and Hani swore. electron camera n. a camera employing electron beams; spec. a television camera that converts an optical image directly into an electrical signal. ΚΠ 1930 G. P. Thomson & C. G. Fraser in Proc. Royal Soc. A. 128 641 The apparatus described in this paper, which will be called for shortness an electron camera, is intended to study the diffraction patterns formed by the reflection of cathode rays from crystalline surfaces. 1937 Discovery Nov. 329/1 The electron camera at the transmitter, with a cathode-ray tube at the receiving end. 1999 Jrnl. Nucl. Med. 40 868/1 This ‘electron camera’ is a serious rival to existing autoradiographic techniques. electron cloud n. Physics the electrons surrounding the nucleus of an atom, viewed as a cloud-like mass. ΚΠ 1920 Proc. Physical Soc. 33 114 The change in the distribution of the electron cloud which must occur when the voltage was applied might be responsible. 1946 Nature 16 Nov. 717/1 In the absence of a magnetic field, the electron-cloud in the outer incomplete shells of the atom or the molecule react [sic] on the nucleus. 2002 U.S. News & World Rep. 9 Sept. 68/2 Friction requires movement, but stationary atoms can also cling together briefly as the random shifting of their electron clouds grant each a transient electric charge. electron-deficient adj. Chemistry having fewer electrons than normal; spec. containing a chemical bond in which a pair of electrons is shared between more than two atoms. ΚΠ 1939 Jrnl. Amer. Chem. Soc. 61 1597/2 It is suggested that the common factor in these reactions is the electron-deficient nature of the catalyst. 1955 Q. Rev. Chem. Soc. 9 176 The boron hydrides and some of their derivatives are examples of electron-deficient compounds. 1995 D. M. P. Mingos Essent. Inorg. Chem. 1 (1997) 30 An electron deficient molecule has fewer valence electrons involved in covalent bonds than the number of orbitals available. 2002 New Scientist 2 Feb. 21/2 On the opposite side, they placed an electron ‘collector’ doped with electron-deficient impurities. These have lots of missing electrons, effectively creating positive ‘holes’. electron-dense adj. Biology and Medicine (chiefly with reference to electron microscopy) opaque to the passage of electrons. ΚΠ 1951 Biochimica et Biophysica Acta 7 179 Further washing of cell walls from Strep. faecalis with distilled water on the high speed centrifuge resulted in the removal of residual electron-dense cytoplasmic material. 1987 J. V. Priestley in A. J. Turner & H. S. Bachelard Neurochem. iii. 85 The oxidized..product..chelates with OsO₄ to form a highly electron-dense product. 1995 C. Nielsen Animal Evol. xvii. 128 The microvilli often terminate in a small knob and there is in many cases an electron-dense epicuticle at the surface. electron density n. the number of electrons per unit volume; (Chemistry) the quantum-mechanical probability that an electron will be found at a given point in an atom, molecule, etc. ΚΠ 1908 Jrnl. Amer. Chem. Soc. 30 1726 Müller also recognizes that his view does not show in any way how the different electrolytes affect the electron density. 1939 L. Pauling Nature Chem. Bond i. 29 The electron distribution function for a poly-electronic atom or ion shows the presence of electron shells as regions of maximum electron density. 1972 Jrnl. Brit. Astron. Assoc. 82 306 Assuming that the coronal electron densities were those given by the model due to Blaumbach and Allen,..the radial velocity components of the emissive regions were calculated. 1995 D. M. P. Mingos Essent. Inorg. Chem. 1 (1997) 17 The π-bonds have a nodal plane, i.e. a region of zero electron density in the plane containing the atoms. electron diffraction n. Science the diffraction of a beam of electrons; frequently attributive. ΚΠ 1927 Physical Rev. Dec. 705 The spacing factor concerned in electron diffraction by a nickel crystal. 1939 Nature 25 Feb. 372/2 Details of their Finch electron diffraction camera intended for industrial research. 1958 Jrnl. Iron & Steel Inst. 189 56/2 The marked thinness of the blades and prisms..resulted in electron diffraction patterns being observed. 1978 G. C. Hill & J. S. Holman Chem. in Context viii. 101 The presence of dimerized pairs of carboxylic acid molecules in benzene has been confirmed by electron diffraction measurements. 2001 R. W. Cahn Coming of Materials Sci. vi. 246 The important techniques of characterising surfaces, such as low-energy electron diffraction, have only been skirted. electron donor n. Chemistry an atom, molecule, etc., which can donate electrons to an electron acceptor. ΚΠ 1929 Jrnl. Physical Chem. 33 261 In point of fact, a direct photomechanical action of radiation upon matter has been..more specifically worked out by F. Weigert for paired systems (atoms or atom groups) of electron donors and electron acceptors. 1978 G. C. Hill & J. S. Holman Chem. in Context xiii. 186 The oxidizing agent (oxidant) is the electron acceptor and the reducing agent (reductant) is the electron donor. 2005 C. de Duve Singularities v. 51 The so-called heterotrophic theory of the origin of life..implies that some of these products of cosmic and prebiotic Earth chemistry acted as the first electron donors,..and that the electrons were caught by some mineral acceptors. electron gas n. Science a system of electrons, typically within a solid, which is unconstrained by individual atoms or molecules and can be approximately described using the kinetic theory of gases. ΘΚΠ the world > matter > physics > atomic physics > particle physics > particle avoiding strong interaction > electron > [noun] > space filled with particles electron gas1913 sea1955 1913 W. H. Keesom in Proc. Section Sci. Koninklijke Akad. van Wetenschappen te Amsterdam 16 236 The frequencies in an electron gas with the same order of magnitude of the number of particles per unit of volume, become very much higher than in the ordinary material gases. 1962 Listener 10 May 809/2 A few free electrons, drifting about hither and thither and forming an electron-gas in the metal. 2001 O. Sacks Uncle Tungsten xxiv. 303 It was also wondered..what might happen to the ‘electron gas’ in metals if they were cooled to temperatures near absolute zero. electron gun n. Science a device in which electrons obtained by thermionic emission from a heated cathode are emitted as a narrow beam. ΘΚΠ the world > matter > physics > atomic physics > particle physics > particle avoiding strong interaction > electron > [noun] > device emitting beams electron gun1924 gun1933 undulator1951 1924 Brass World Feb. 52/1 The electron gun is not swung about, but its stream of projectiles is deflected by means of electric or magnetic forces. 1930 Chem. Abstr. 2044 The electron gun..consists of a hot filament near the small hole in a diaphragm and on the axis of a hollow cylinder at a pos. potential, which produces a ‘visible’ beam of electrons. 1953 S. W. Amos & D. C. Birkinshaw Television Engin. I. iv. 52 The electron gun is an electrode assembly designed to produce a narrow beam of electrons. 1991 Engineering July–Aug. 40/1 Ingress of metal vapour into the electron gun during welding can cause high voltage breakage between gun electrodes. 2005 Sci. Amer. (U.K. ed.) June 82/1 I replaced my electron-gun boob tube with a 42-inch plasma flat panel. electron lens n. Physics a device for modifying an electron beam in the same way as an ordinary lens modifies a light beam. ΚΠ 1931 Physical Rev. 1 Aug. 585 (heading) Electron lenses. 1949 Proc. Royal Soc. A. 197 456 An electron gun, combined with a suitable aperture and electron lens system, produces a coherent illuminating beam. 1999 D. Mitchell Ghostwritten 389 EyeSat 46SC was designed to track hurricanes from the Caribbean to the States on the Gulf of Mexico. It was later modified to combat drug trafficking, and fitted with the most powerful terrestrial-facing electronlens ever sent into space. electron-lucent adj. Biology and Medicine (chiefly with reference to electron microscopy) transparent to electrons. ΚΠ 1953 Jrnl. Exper. Med. 98 610 The cytoplasmic matrix is essentially electron-lucent except for variable concentrations of granules. 1995 C. Nielsen Animal Evol. xxxviii. 294 The ectoderm is monolayered and covered by a chitinous cuticle,..with an electron-dense outer and a homogeneous, electron-lucent inner zone. electron microgram n. = electron micrograph n. ΚΠ 1943 Jrnl. Amer. Med. Assoc. 16 Oct. 400/2 Figure 1 shows an electronmicrogram (1 × 14,500) of a sample of purified SK murine virus. 2005 Colloids & Surfaces B. 46 138 (caption) Scanning electron microgram (SEM) of calcium lactate pentahydrate and its anhydrate. electron micrograph n. a micrograph produced by an electron microscope. ΚΠ 1934 Sci. Abstr. A. 37 203 The electron micrographs, taken with a kathode temperature of 1000° C., showed the crystalline surface structure of the nickel. 1946 A. Nelson Princ. Agric. Bot. xxiv. Plate 100 (caption) Electron micrograph of a dried film of purified tobacco mosaic virus. 1992 D. V. Parums in C. E. Lewis & J. O'D. McGee Macrophage ix. 371 (caption) A transmission electron micrograph showing a vasa vasorum in the aortic adventitia of a patient with advanced atherosclerosis. electron micrographic adj. relating to or obtained by electron micrography. ΚΠ 1944 Jrnl. Biol. Chem. 156 598 The difference probably was related to the measurement of the images irrespective of orientation on the electron micrographic plates. 1998 Proc. National Acad. Sci. U.S.A. 95 6236/2 The electron micrographic evidence for paracrystallinity of the protein filaments from silica spicules of another sponge. electron micrography n. the making and interpretation of electron micrographs. ΚΠ 1941 Amer. Jrnl. Pathol. 17 576 (heading) The electron micrography of purified viruses. 1968 C. W. Schwabe & A. Kilejian in M. Florkin & B. T. Scheer Chem. Zool. II. iii. vi. 472 By electron micrography, several workers..have shown that the integument of some adult and larval tapeworms is covered with minute ‘villi’. 2006 Jrnl. Colloid & Interface Sci. 304 1 Characterization of these particles was carried out using transmission electron micrography (TEM), and vibrating sample magnetometry (VSM). electron microprobe n. a device for focusing a narrow beam of electrons on to a minute area of a sample, exciting phenomena (esp. X-ray fluorescence) which can be analysed to yield chemical or structural information; a microanalytical instrument incorporating such a probe; cf. microanalyser n.; frequently attributive. ΚΠ 1959 Endeavour Apr. 86/1 Perhaps the most important development of X-ray spectroscopy during the last few years is that using the various electron microprobe techniques originating in work by R. Castaing. 1961 Science 8 Dec. 1938/2 The degree of destructiveness of the electron microprobe is not yet established, but..I believe conventional mass spectroscopy cannot hope to match it in nondestructiveness. 1977 A. Hallam Planet Earth 17/1 Tiny crystals that can be analysed only by use of a special instrument, the electron microprobe. 2001 Powder Diffraction 16 92 Electron microprobe analysis confirmed K:Pb:S as 2:1:2 for the annealed palmierite powder. electron multiplier n. Electronics an instrument for amplifying the intensity of a small current of electrons, typically by means of secondary emission at each of a succession of electrodes; cf. multiplier n. 4. ΚΠ 1934 Electronics 7 242 An electron multiplier. A new type of cold-cathode tube of high current amplifying ability marks another step toward the solution of television problems. 1953 S. W. Amos & D. C. Birkinshaw Television Engin. I. v. 107 If the return beam is directed into an electron multiplier the tube output can be increased. 2007 Radiation Physics & Chem. 76 384/1 They replaced the electrostatic analyzer with a rotatable channel electron multiplier. electron neutrino n. Particle Physics a type or flavour (flavour n. 5) of neutrino associated with reactions involving electrons (one of the three known types of neutrino); cf. muon neutrino n. at muon n. Compounds, tau neutrino n. at tau n. Compounds 3. ΚΠ 1959 Žurnal Eksperimental′noj i Teoretičeskoj Fiziki 37 1751 (title) Electron and muon neutrinos. 1993 Guardian 26 Aug. ii. 17/4 Natural radioactivity and fusion in the sun produce electron-neutrinos; experiments at accelerators and cosmic rays show that there are also two other varieties in nature, known as the muon-neutrino and tau-neutrino. 2003 Astroparticle Physics 20 197/1 RICE was originally conceived as an experiment to search for electron neutrinos. electron optics n. [in sense (a) after German Elektronenoptik (A. Heydeweiller 1915, in Verhandl. der Deutsch. Physikalischen Ges. 17 359); in sense (b) after German Elektronenoptik (Knoll & Ruska 1932, in Ann. der Physik 12 607)] Physics (a) optical properties as ascertained from or related to electronic properties (rare, now disused); (b) a branch of physics concerned with the influence of electric and magnetic fields on the movement of electrons. ΚΠ 1916 Chem. Abstr. 10 299 The number of these latter electrons is not definitely known, but is almost surely greater than 1, from considerations of the electron-optics of the H-cation in H₂O. 1932 Sci. Abstr. A. 35 645 Application of geometric electron optics makes it possible to explain the behaviour of the beam in an electron tube. 1969 Times 28 Mar. 25/3 The British company claims to have gained the lead, with some Government financial aid, through its expertise in precision and electron optics. 1990 Proc. Royal Microsc. Soc. 25 339/3 (advt.) Optimum conditions for a contamination-free specimen environment and maximum cleanliness of the electron optics. 2007 Ultramicroscopy 107 174/1 One can presuppose that the magnitude of lens errors in electron optics is very small. electron-optical adj. Physics of or relating to electron optics; employing or involving electron optics. ΚΠ 1933 Sci. Abstr. A. 36 199 A combined electric and magnetic deflection method which gives electron-optical enlargements of emitting surfaces. 1951 Engineering 13 July 40/2 A tube with sufficiently good electron-optical focus for high-definition pictures was made. 1977 Jrnl. Royal Soc. Arts 125 772/2 Direct linear measurement of pulse durations by electronoptical streak-cameras. 2007 Ultramicroscopy 107 106 An electron-optical effect caused by specimen charging. electron pair n. Chemistry and Physics a linked or interacting pair of electrons; spec. (a) two electrons with opposite spins occupying the same orbital in an atom or molecule; cf. duplet n. 2; (b) an electron and a positron formed by decay of a gamma-ray photon; cf. pair production n. at pair n.¹ Compounds 1. ΚΠ 1910 London, Edinb., & Dublin Philos. Mag. 6th Ser. 19 1 The special electron pair consists of a positive electron which acts as though uniformly distributed through a sphere of radius R = 0.795 x 10^-8... The negative electron is situated at distance r along the electric axis of the atom from the centre of the sphere of radius R. 1923 G. N. Lewis Valence vi. 83 We may suppose that the normal state of the hydrogen molecule is one in which the electron pair is symmetrically placed between the two atoms. 1933 R. A. Millikan in Science 25 Aug. 154/2 A free positive and negative electron-pair often result from the collision of a sufficiently energetic photon with an atomic nucleus. 1958 O. R. Frisch Nucl. Handbk. viii. 12 Electron pairs can be created by other processes including: (a) Passage of a heavy particle through matter..(b) Passage of a fast electron through the field of a nucleus..(c) Collision between two electrons. 1964 J. W. Linnett Electronic Struct. Molecules ii. 28 This difficulty of solving the Schrödinger equation for systems containing two or more electrons means that the development of the electron-pair bond has to be based, to a large extent, on empirical reasoning. 1995 D. M. P. Mingos Essent. Inorg. Chem. 1 (1997) 8 Classically the bond order is the number of electron pairs being shared between connected atoms. electron probe n. = electron microprobe n. ΚΠ 1943 Science 17 Dec. 10/1 In the electron microanalyzer a very small area of the specimen is irradiated with an electron probe, a stream of these particles of electricity brought into a beam by a two-stage magnetic lens system. 1972 R. Galopin & N. F. M. Henry Microsc. Study Opaque Minerals i. 6/1 The modern micro-beam electron probe is the almost perfect instrument in the chemical study of fine-grained materials. 1989 Brit. Archaeol. May–June 28/2 A fragment of the plate has now been examined..using modern metallography and electron probe microanalysis. electron spin n. Particle Physics the intrinsic angular momentum of an electron, denoted by the quantum number s; the property of an electron by virtue of which it possesses this momentum. ΚΠ 1926 Nature 20 Feb. 264/2 The dotted lines represent the position of the energy levels to be expected in the absence of the spin of the electron.] 1926 Proc. National Acad. Sci. U.S.A. 12 452 There seems to be no reason a priori why the magneto-magnetical ratio for the electron spin should be even of the same order of magnitude as for an electron revolving in an orbit. 1935 A. Farkas Orthohydrogen, Parahydrogen & Heavy Hydrogen ii. 4 The distinction between the hydrogen modifications is based on the different orientations of the nuclear spins, while in the case of helium it depends on the orientation of the electron spins. 1992 D. G. Campbell Crystal Desert x. 197 Magnetite is a mixture of ferric and ferrous iron, which have opposite electron spins and therefore create a miniature magnetic dipole. electron spin resonance n. Physics and Chemistry resonance (sense 5c) in which the transition involved is that of electrons between states of different spin, esp. unpaired bound electrons in a paramagnetic ion; abbreviated ESR. ΘΚΠ the world > matter > physics > quantum theory > electron spin > [noun] > electron spin resonance electron spin resonance1952 ESR1955 the world > matter > physics > atomic physics > decomposition of light, spectrum > study of spectra > types of spectrometry or spectroscopy > [noun] > electron spin resonance spectroscopy electron spin resonance1952 ESR1955 1952 Physical Rev. 15 Nov. 951/1 We have observed conduction electron spin resonance absorption in fine particles of metallic sodium..at a frequency of 9240 Mc/sec. 1972 R. A. Jackson Mechanism iv. 61 Electron spin resonance spectroscopy, which is very sensitive and will detect radical concentrations down to about 10⁻⁹ m, is extremely useful. 2003 B. Bryson Short Hist. Nearly Everything (2004) x. 199 Scientists devised other methods of dating ancient materials, among them..electron spin resonance, which involves bombarding a sample with electromagnetic waves and measuring the vibrations of the electrons. electron telescope n. Astronomy a telescope that detects incident electrons or electrons generated by incident light.Early kinds used the principle of a photoelectric detector; later ones that of a scintillation counter. ΚΠ 1937 Technol. Trends & National Policy (U.S. National Resources Comm.: Subcomm. on Technol.) i. iii. 29 Particularly promising and perhaps some day needing legislative enforcement, are the uses of infrared light, with the electron telescope, for sighting through fog the sun, the signal lights and hot funnels of an approaching ship. 1948 Jrnl. Brit. Interplanetary Soc. Nov. 250 The ‘electron telescope’ has been used to make visible stars which could not otherwise be detected. 2007 Planetary & Space Sci. 55 2/1 The Kiel Electron Telescope (KET) is designed to measure electron intensities for energies above 2.5 MeV. electron tube n. a vacuum tube containing two or more electrodes, such that a current can flow in a controlled way between them; spec. a thermionic valve (= tube n. 2g(b)); (also) a gas-filled tube in which an electric discharge takes place.For the spec. sense, valve is the usual term in British English, and tube in American English. ΘΚΠ the world > matter > physics > electromagnetic radiation > electronics > electronic devices or components > thermionic valve > [noun] > vacuum tube or thermionic valve vacuum tube1859 trigger tube1894 audion1906 pliotron1915 diode1919 electron tube1919 negatron1919 pentode1919 power valve1919 tetrode1919 triode valve1919 magnetron1921 bright emitter1923 peanut valve1923 peanut1924 power tube1924 multiple valve1929 thyratron1929 heptode1932 hexode1933 pentagrid1933 acorn tube1934 octode1934 triode-pentode1936 triode-hexode1937 transitron1939 trochotron1947 steering diode1957 1919 Science 21 Nov. 478/1 ‘Theory of action of electron tubes as amplifiers,’ John M. Miller, Bureau of Standards. 1930 Electronics Apr. 25/2 The electron-tube control of the stage lighting in the..Chicago Civic Opera House. 1964 L. H. Van Vlack Elements Materials Sci. (ed. 2) 409 (Gloss.) Transistor , an electrical device utilizing semiconductors and performing some of the functions of electron tubes. 1996 E. Sridharan Polit. Econ. Industr. Promotion ii. 28 Electron tubes can be of many types, the best known being the TV picture tube. electron wave n. Physics the wave associated with the movement of an electron and held to account for its wave-like properties; a de Broglie wave of an electron. ΚΠ 1927 Proc. National Acad. Sci. U.S.A. 13 460 A single plane of atoms reflects a very appreciable fraction of the electron wave, whereas the same plane would reflect only an inappreciable part of an X-ray wave. 1958 E. U. Condon & H. Odishaw Handbk. Physics viii. vi. 77/2 The small periodic deviations of the emission current..come about through the interference effect of electron waves. 2007 Radiation Physics & Chem. 76 213/2 Thin objects, that consist mainly of light atoms (H, C, N, O, S, etc.), are basically transparent to the incident electron wave. This entry has been updated (OED Third Edition, June 2008; most recently modified version published online March 2022). < n.¹1856n.²1891
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electronn.1

electronn.2

Compounds

electronn.¹

electronn.²