The de Broglie Waves and the Davisson-Germer Experiment

The de Broglie hypothesis was put forward by Louis de Broglie. According to him, just like the particles of light, every material particle shows a dual character. There's a wave associated with every material particle such as an electron. He even calculated the wavelength of these matter waves by using Einstein's and Planck's formulae.

de Broglie did not have any experimental evidence to prove his hypothesis. The experimental verification of de Broglie waves came four years later, in 1927, when two scientists named Davisson and Germer were studying the angular distribution of electrons after they are scattered off nickel foil. Due to some complications, they had to treat the nickel foil with heat. After they performed the experiment again, the results completely changed.

They saw that most of the electrons were being scattered at a particular angle that was a function of the initial kinetic energy of the electrons. There was not a single peak though. There were multiple angles at which the scattering was more.

This happened because when the nickel foil was given heat treatment, it got crystallized. The atoms arranged themselves in regular planes and hence the the incoming electrons got diffracted.

Davisson-Germer experiment is one of the most important experiments in quantum mechanics.

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