de Broglie Confirmation

Davisson and Germer's accident

  • Davisson and Germer studied the surface of a piece of nickel by examining the scattering of electrons from it.
  • The surface consisted of many microscopic crystals bonded together at random orientations, and thus would appear rough to the electrons, hence would produce a deflection pattern.
  • However, during the course of their experiment, air entered the vacuum chamber that held the nickel crystal, and an oxide film formed on the surface.
  • To remove this film, the metal was heated just below the melting point in a process called annealing.
  • Annealing actually causes the metal to form a smooth layer, with the crystal lattice structure being regular and uniform. Now electrons do not perceive the lattice to be rough but smooth.
  • It caused the lattice to become a suitable diffraction grating for the electrons.
  • This produced some vastly different results.
  • The electron detector now longer produce a distribution pattern but maxima and minima (or diffraction pattern) due to the constructive and the deconstructive interference .
  • It is important to note that diffraction patterns can only result from waves colliding into the regular spacing of a diffraction grating, producing the constructive/deconstructive interference.
  • This is a property of waves, this gives extremely strong evidence for the wave-particle duality of electrons.
  • This confirmed de Broglie's 'matter-wave' proposal.