Physics Help Forum Radius of Gyration of an H-polymer?

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 Sep 29th 2019, 08:29 AM #1 Junior Member   Join Date: Sep 2019 Posts: 1 Radius of Gyration of an H-polymer? Hello, I've been struggling with determining the radius of gyration of an H-polymer. Show that the radius of gyration of an ideal H-polymer with all five sections containing an equal number (N/5) of Kuhn monomers of length b is: $\displaystyle (R_g)^2 = (Nb^2/6)(89/625)$ I know the definition of the radius of gyration, but I've been having a difficult time deducing this particular equation from there. Any help is appreciated.
 Sep 30th 2019, 04:01 AM #2 Senior Member   Join Date: Oct 2017 Location: Glasgow Posts: 474 I don't know anything about physical chemistry, but it seems to me that there is a specific equation for the radius of gyration for a polymer based on the square of the distance between each point in the polymer chain and the centre of mass of the chain: $\displaystyle ^2 = \frac{1}{N} \sum_{i=1}^{N} (R_i - R_{cm})^2$ So, perhaps you can draw the basic structure of a H-polymer with 5 sections and calculate this summation for each point on the polymer from its centre of mass? topsquark likes this.

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