19
Light scattering is not limited to a single particle. Particles are moving
in solution, bouncing into and off of each other, and light does the
same. Since we are concerned with elastic scattering, this phenomenon
does not result in a loss of intensity, but it becomes more challenging
to accurately measure particle diffusion if the light path is interrupted
by more than one particle on its way to the detector.
DLS instrumentations generally work with very small sample volumes.
This allows for fewer multi-scattering events because there are fewer
particles in the light's pathway, so it is more likely the light will only
be scattered by a single particle. Additionally, instrumentation has
very precisely focused lasers and detectors in order to keep the area
being measured small. DLS instruments are carefully designed to
minimize the effects of multi-scattering events in solution.
Multi-scattering events
