Third‐order interaction approximation for linear polymer chains

Abstract

Abstract Third‐order interactions imposed by a pair of atoms separated by five bonds are taken into account in computations of the mean‐square end‐to‐end distance and the mean‐square radius of gyration for linear polymer chains. The statistical weight matrices are established on the basis of the rotational isomeric state model. The conformational energy of n ‐hexane is calculated as a function of the CC bond rotation angles. The third‐order interaction energy is obtained by comparison with that of n ‐pentane. The characteristic ratio of polymethylene is 6.6 in the third‐order interaction approximation, which is in agreement with experimental data.