Dynamic Structure Factor and Mean Square Displacement

1 Dynamic Structure Factor and Mean Square Displacement Here we learn how gi(T) obtained in DLS gives an estimate of the diffusion coefficient. We are concerned with dilute solutions here. Hence, gi(T) = Si(k, t). 

Ifplotsof ln gi(T) /k vs. Tmeasured at different angles overlap each other, then A is already sufficiently small. Typically, k X (size of the particle) 1 qualifies as small k. 

The mean square displacement in time r is evaluated by using Eq. 3.40. The slope in the plot is equal to 6D. It is, however, more common to follow the approach described below. 

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