Electron Diffraction

In this equation, h is Planck’s constant and E = p/(2m) is the kinetic energy of the particle in the non-relativistic regime. The wave aspect of particles was demonstrated first by an experiment on electron diffraction performed by C. H. Davisson and L. H. Germer. For his hypothesis on the wave nature of particles de Broglie was awarded the Nobel Prize in Physics in 1929, and Davisson and Germer received the 1937 Nobel Prize for their experiment. The Davisson and Germer experiment had a beam of electrons with a well defined wavelength shorter than the spacing between atoms in a target metal crystal reflecting from its surface; at particular angles of reflection they detected a large increase in the reflected intensity corresponding to diffraction peaks much like one can see nowadays on reflection from a grating using a laser. An elementary description of the de Broglie hypothesis and of the Davisson and Germer experiments can be found in any introductory physics book with some modern physics chapters [1, for example]. An excellent description of a more modern electron source and reflection diffraction from a graphite crystal and the crystal with a single layer of Krypton atoms on top can be found in the short article by M. D. Chinn and S. C. Fain, Jr. [2].