# Dynamic Light Scattering based o Rayleigh or Mie theory?

I know the difference between Rayleigh and Mie scattering theory, but I am confused regarding: Dynamic Light Scattering theory.

Is this last one constructed using Rayleigh theory or Mie theory?

Thank you

## 1 Answer

It is described using Rayleigh scattering. Dynamic light scattering is used to describe the size distribution profile of small particles.

Now because these are small particles, they can be described using Rayleigh scattering if the wavelength of the light is bigger then the size of the particles.

https://en.wikipedia.org/wiki/Dynamic_light_scattering

Rayleigh scattering (/ˈreɪli/ RAY-lee), named after the nineteenth-century British physicist Lord Rayleigh (John William Strutt),[1] is the predominantly elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the radiation.

https://en.wikipedia.org/wiki/Rayleigh_scattering

Mie scattering is used when the wavelength is comparable (similar) to the size of the particles.

But in your case, the particles are smaller then the wavelength of light, that is why they use Rayleigh scattering.

• Have you gone through the math of Dynamic Light Scattering theory "DLS"? Because I have gone through some of it in a book, and I have never seen they use any assumption or results from Rayleigh scattring. So my new question is where and when is Rayleigh theory used for deriving DLS theory?
– Who
Oct 11 '19 at 11:39
• Oct 11 '19 at 17:02