TDFRS Versus PCS

Naturally, all experimental techniques that allow the measurement of diffusion coefficients must be compared to PCS, which is the most widely employed method for the study of polymer diffusion processes. 

The normalized electric field autocorrelation function gift), which can be calculated from the normalized intensity autocorrelation function g2(t) = (1(0) 7(f)) (I(0)/2 according to the Siegert relation [56] 

Before the relative statistical weights can be compared, it is necessary to relate the diffusion coefficient D to the molar mass M. Usually, this can be done by a scaling relation 

It should be noted that Eq. (39) is slightly different from the usual definition, where a M b is employed for D, not r. a, as defined in Eq. (39), is (/-dependent because of the q2. 

From Eq. (39), the amplitude factors in Eq. (33) can be expressed as a function of molar mass and concentration, and the normalized decay function for a dilute polymer solution, which is et(t) in case of TDFRS andgj (t) in case of PCS, can be written as 

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