Determination of Large Molecular Weights by Fluctuation Spectroscopy with Quasielastic Light Scattering
A new method is proposed to determine the molecular weight M of large molecules by observing the probability distribution function of the fluctuation of quasielastic light scattering.. The experimental system used is depicted in Figure 1. The quasielastic light I (t) scattered by molecules in a finite volume V is detected by a pnoto-multiplier tube. The photocurrent is amplified, and passed through a low pass filter having a cutoff frequency of ωc. The low pass filter is used to reduce the fluctuation of the photocurrent not associated with the number fluctuation. The probability distribution function of the photocurrent fluctuation is calculated with a correlator and then analyzed with a minicomputer.
KeywordsProbability Distribution Function Diffusion Constant Shot Noise Large Molecular Weight Weight Concentration
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- 1.K. Ohbayashi, M. Minoda, and H. Utiyama, Macromolecule vol. 14 (1981).Google Scholar