# Dynamic Light Scattering

The correlation function for a system experiencing Brownian motion $$G(t)$$ decays exponentially with decay constant $$\Gamma$$.

$G(t)=e^{-\Gamma t}$

$$\Gamma$$ is related to the diffusivity of the particle by

$\Gamma=-Dq^{^{2}}$

where

$q=\frac{4\pi n }{\lambda}\sin(\dfrac{\Theta }{2})$