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There are two kinds of scattering relevant for DLS. Both of
them are considered "elastic" scattering, which means there
is no loss in the energy of the photon – i.e. the wavelength
does not change when it encounters the particle in solution.
The first is Rayleigh scattering. This is a phenomenon that
occurs when a particle is much smaller than the incident
light wavelength, typically less than 1/10th. In this scattering
phenomenon, the radiated light scatters about evenly in all
directions – i.e., the intensity does not significantly change
based on its reflection angle. Note that there is a slight
"node" in light scattering at angles 90
o
to the incident light,
hence it is not a perfectly even phenomenon.
Scattering phenomena
