THE EXPERIMENTS CONFIRMING THE WAVE STRUCTURE OF THE ELECTRON

- Computer programm - experiment simalation

In 1925 Clinton Davisson and C.H. Kunsman (later also Laster Germer) begun to conduct the experiments which confirmed the de Broglie's theory. They shot the crystal of nickel with a beam of electrons from the glowing cathode. That caused a secondary emission of electrons from the crystal. The number of the electrons sent in different directions was defined using the collector - a metal plate which incidencing electrons. The collector could have been moved around the crystal. By the accident the one of the nickel plates oxidised. To remove nickelic peroxide the plate was heated. After that the plate was used again in the experiment. But the results occurred to be completely different than before. That was because the method of cleaning the plate changed it in a big monocrystal. The electrons were emit from such plate in all directions but at some angles the emission was bigger. For the beam of electrons of the energy of 54 MeV the angle of the increased emission was equal about 500. The momentum of the electrons is given by a formula:

(1)

where m0 is the rest mass of the electron, E is the energy of the electron. The angles at which the diffraction maximums occur can be calculated knowing the wave length and the construction of the diffraction grating. From the other hand the wave length can be calculated knowing the angles of the maximums and the characteristic of the grating. The wave length calculated by the scientists was equal 1,65*10-10 m. According to the de Broglie's wave theory the wave length of the electron when the wave is of the energy of 54 MeV is equal 1,67*10-10 m. Conformity of the two values confirmed the wave structure of the electron.

At the same time George Paget Thomson (1892-1975) (J.J. Thomson's son) conducted a different experiment and also proved the wave structure of electrons. The thin (about 10-5 cm) gold foil was bombarding by a beam of electrons of a high velocity (of the energy of about 104 eV). The electrons went through the foil but when they did diffraction occurred. Thomson observed the diffraction rings on the screen behind the foil. The rings were the proof for the wave structure of the electrons.
The two described above experiments were the most important ones confiming the wave nature of the electron. In 1937 Clinton Joseph Davisson and George Paget Thomson received the Nobel Prize.
But there were more such experiments conducted.
For example the German scientist Rupp measured the length of the electrons wave. He used the phenomena of the diffraction of the beam of electrons on the optical diffraction grating.

Soon it was also proved that the other particles are also of the wave nature.
In 1931 Johnson noticed the diffraction of the beams of hydrogen particles scattered on crystals, and in 1938 Stern, Easterman, and Frisch observed the diffraction of the beam of helium particles on a crystal.

SCHUSTER'S EXPERIMENT  |   THOMSON'S EXPERIMENT  |   MILLIKAN'S EXPERIMENT  |   RUTHERFORD'S EXPERIMENT  |   ASTON'S EXPERIMENT  |   ELECTRON'S WAVE STRUCTURE - EXPERIMENTS  |   FRANCK'S-HERTZ'S EXPERIMENT  |   STERN'S-GERLACH'S EXPERIMENT  |   COMPTON'S PHENOMENON