freely rotating chain

in polymers
https://doi.org/10.1351/goldbook.F02518
A hypothetical @L03546@ molecule, free from short-range and long-range interactions, consisting of infinitely thin rectilinear segments (bonds) of fixed length, jointed at fixed bond angles; the torsion angles of the bonds can assume all values with equal @P04855@.
Source:
Purple Book, 1st ed., p. 50 [Terms]