In the scope of DLS, temporal fluctuations are usually analyzed using the intensity or photon auto-correlation function (also known as photon correlation spectroscopy - PCS or quasi-elastic light scattering - QELS). In the time domain analysis, the autocorrelation function (ACF) usually decays starting from zero delay time, and faster dynamics due to smaller particles lead to faster decorrelation of scattered intensity trace.
In DLS, temporal fluctuations are typically analyzed using either photon auto-correlation spectroscopy (PCS) or quasi-elastic light scattering (QELS). In the time domain analysis, the autocorrelation function (ACF) decays from zero delay time and faster dynamics in smaller particles lead to quicker decorrelation of scattered intensity.