https://doi.org/10.1351/goldbook.12202
Square root of the ratio of the unperturbed mean-square end-to-end distance of a linear chain to its number of skeletal bonds, i.e., \[b = (\lt\!r_{\rm{o}}^{2}\!\gt\!/n)^{1/2}\]
Notes:
- The effective bond length is a type of characteristic ratio relating to chain structure, cf., characteristic ratio.
- \(b^{2}\) is the unperturbed mean-square end-to-end distance per skeletal bond. For a hypothetical, sufficiently long chain of identical single skeletal bonds having rotational isomeric states that are independent of each other, the equation in mean-square unperturbed end-to-end distance shows that the value of \(b\) depends on the values of \(l\), \(\cos \theta\) and \(\lt\!\cos \phi\!\gt\). In general, for actual chains, the value of \(b\) is still characteristic of the values of the lengths and valence angles of the skeletal bonds and of the dihedral bond-conformational angles, although it may be difficult to write an analytical expression for \(b\).