## Diffraction patterns

$E=hv$

Posts: 134
Joined: Sat Sep 14, 2019 12:17 am

### Diffraction patterns

We learned that electrons passing through crystals show diffraction patterns... why does this necessarily mean?

Naji Sarsam 1F
Posts: 104
Joined: Sat Aug 17, 2019 12:18 am

### Re: Diffraction patterns

To understand diffraction patterns, one must first recognize that there are two models possible for understanding the motion of an object relevant to chemistry: the particle model and the wave model. The particle model interprets objects as solid objects which have a defined location in space. The wave model interprets objects as waves throughout a medium--such as sound waves being waves through solid material or light waves being waves of electromagnetic radiation.

The key difference between these models is that the motion of particles differs greatly for that of waves. While particles can only be in one location at one time, waves radiate out in all directions.

The experiment being discussed involves electrons being shot through a crystal of atoms. Crystals of atoms are lattices, meaning they are repeating patterns of the atoms. If electrons were particles, the detector behind the crystal should only observe electrons coming through the spaces between atoms. It should not observe electrons appearing directly behind atoms because particles would not be able to pass through the nucleus of an atom. However, this pattern is what is detected. This reveals that electrons must be waves which can pass through the spaces between atoms and interact with itself--just as light does in the double-slit experiment. If the electron wave constructively interferes with itself behind an atom, thats how electrons can be detected there.

Helen Struble 2F
Posts: 97
Joined: Sat Aug 24, 2019 12:17 am

### Re: Diffraction patterns

The diffraction patterns exhibited by electrons prove that electrons exhibit wave-like properties as well as typical particle-like properties. Diffraction is a phenomenon which occurs in waves which are directed at an obstacle or slit which is similar in size to the wavelength. Because diffraction is a property of waves, it must be concluded that electrons behave like waves and like particles.