electron diffraction

electron diffraction
the phenomenon whereby electron waves scattered by the regularly spaced atoms of a crystal produce diffraction patterns characteristic of the crystal structure and the wavelength.
[1925-30]

* * *

      interference effects owing to the wavelike nature of a beam of electrons (electron beam) when passing near matter. According to the proposal (1924) of the French physicist Louis de Broglie (Broglie, Louis-Victor, 7e duc de), electrons and other particles have wavelengths that are inversely proportional to their momentum. Consequently, high-speed electrons have short wavelengths, a range of which are comparable to the spacings between atomic layers in crystals. A beam of such high-speed electrons should undergo diffraction, a characteristic wave effect, when directed through thin sheets of material or when reflected from the faces of crystals. Electron diffraction, in fact, was observed (1927) by C.J. Davisson and L.H. Germer in New York and by G.P. Thomson in Aberdeen, Scot. The wavelike nature of electron beams was thereby experimentally established, thus supporting an underlying principle of quantum mechanics.

      As an analytic method, electron diffraction is used to identify a substance chemically or to locate the position of atoms in a substance. This information can be read from the patterns that are formed when various portions of the diffracted electron beam cross each other and by interference make a regular arrangement of impact positions, some where many electrons reach and some where few or no electrons reach. Some advanced analytical techniques, such as LEEDX (low-energy electron diffraction), depend on these diffraction patterns to examine solids, liquids, and gases.

* * *


Universalium. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Electron diffraction — is a technique used to study matter by firing electrons at a sample and observing the resulting interference pattern. This phenomenon occurs due to the wave particle duality, which states that a particle of matter (in this case the incident… …   Wikipedia

  • electron diffraction — elektronų difrakcija statusas T sritis fizika atitikmenys: angl. electron diffraction vok. Elektronenbeugung, f; Elektronendiffraktion, f rus. дифракция электронов, f pranc. diffraction électronique, f …   Fizikos terminų žodynas

  • electron diffraction pattern — elektronograma statusas T sritis Standartizacija ir metrologija apibrėžtis Grafinis elektronų difrakcijos vaizdas. atitikmenys: angl. electron diffraction pattern; electronogram vok. Elektronenbeugungsaufnahme, f; Elektronenbeugungsbild, n rus.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • electron diffraction pattern — elektronograma statusas T sritis fizika atitikmenys: angl. electron diffraction pattern; electronogram vok. Elektronenbeugungsaufnahme, f; Elektronenbeugungsbild, n rus. электронограмма, f pranc. diagramme de diffraction d’électrons, m;… …   Fizikos terminų žodynas

  • electron diffraction camera — elektronografas statusas T sritis fizika atitikmenys: angl. electron diffraction camera; electronograph vok. Elektronenbeugungskamera, f; Elektronograph, m rus. электронограф, m pranc. caméra de diffraction électronique, f; électronographe, m …   Fizikos terminų žodynas

  • electron-diffraction crystallography — elektronų difrakcijos kristalografija statusas T sritis fizika atitikmenys: angl. electron diffraction crystallography vok. Elektronendiffraktion Kristallographie, f rus. электронографическая кристаллография, f pranc. cristallographie par… …   Fizikos terminų žodynas

  • electron diffraction camera — elektronografas statusas T sritis Standartizacija ir metrologija apibrėžtis Aparatas, kuriuo sudaromi ir užrašomi difrakciniai vaizdai (elektronogramos), susidarantys pagreitintiems elektronams sklindant per tiriamąją medžiagą. atitikmenys: angl …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • electron-diffraction crystallography — elektronų difrakcijos kristalografija statusas T sritis Standartizacija ir metrologija apibrėžtis Kristalografija, pagrįsta elektronų difrakcija. atitikmenys: angl. electron diffraction crystallography vok. Elektronendiffraktion Kristallographie …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • electron diffraction — noun : an effect due to the wavelike nature of electrons and observed when a narrow beam of them upon passing through a very thin layer of a material (as a metal crystal) is deflected in particular directions and if allowed to fall on a… …   Useful english dictionary

  • Reflection high energy electron diffraction — (RHEED) is a technique used to characterize the surface of crystalline materials. RHEED systems gather information only from the surface layer of the sample, which distinguishes RHEED from other materials characterization methods that rely also… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”