## Wikipedia - Характеристичне співвідношення (uk) characteristic ratio

in polymers
https://doi.org/10.1351/goldbook.C00982
The ratio of the mean-square end-to-end distance, $$< r^{2} >_{0}$$, of a @L03556@ chain in a theta state to $$N\cdot L^{2}$$, where $$N$$ is the number of rigid sections in the main chain, each of length $$L$$; if all of the rigid sections are not of equal length, the mean-square value of $$L$$ is used, i.e. $L^{2}=\sum _{i}\frac{L_{i}^{\bar{2}}}{N}$ In simple single-strand chains, the bonds are taken as the rigid sections. The recommended symbol is: $$C_{N}$$ ($$C_{\infty }$$ when $$N\rightarrow \infty$$).
Source:
Purple Book, 1st ed., p. 49 [Terms] [Book]