Dear Student,

Clinton Davisson and Lester Germer designed the Davisson-Germer experiment from 1923-1927. They built a vacuum apparatus with the intention of measuring the energy of the electrons that scattered from the metal surface. The basis of the experiment was the thought that waves that reflected from the two atomic layers of Ni, would show either constructive interference or destructive interference. This will definitely produce a diffraction pattern. The experiment involved electrons being accelerated by a electrostatic particle accelerator that comprised of two opposite charged plates (positive and negative plate) which were used to accelerate the electrons at a known potential from a heated filament that were made to strike the surface of a metal (Nickel). The Faraday box, that was the electron detector was mounted on an arc to observe the angular deflection of the electrons. The intensity (strength) of the electronic current received by the detector and the scattering angle is studied. This current can be called as the electron intensity. With the variation in the angles, the intensity of the scattered electron beam varied and even showed peaks. In this case, for a particular voltage (54V, say) the maximum scattering happens at a fixed angle only ( 50 degree ).

With the help of electron diffraction, the wavelength of matter waves was calculated to be 0.165 nm. Now, if we correlate the Davison Germer experiment to the de-broglie equation

λ = h/p

λ = 1.227/sq.root 54 = 0.167nm

Thus, it can be concluded that electrons exhibit wave nature too. This supports the hypothesis of de-broglie that stated the wave-particle duality of matter.

Hope this helps! All the best.