Doppler broadening

In atomic physics, Doppler broadening is when spectral lines become wider. This effect is caused by the Doppler effect. Atoms and molecules emit or absorb particles. The atoms and molecules move at many different velocities. When an atom emits a particle, the speed of the particle is similar to the atom that it came from. This means that the particles move at many different velocities. These particles have different amounts of Doppler shifts. This results in emission or absorption line broadening. Emission and absorption lines are measured in a line profile. The widened line profile is called a Doppler profile. 

Doppler broadening can have many different causes. A common type is thermal Doppler broadening. Thermal Doppler broadening is caused by the thermal motion of particles (particles moving in different speeds because of heat).

 References 

Category:Doppler effects
Category:Physical phenomena