Statistical mechanics of helical wormlike chains. XVI. Excluded-volume effect on the mean-square electric dipole moment

Abstract

The expansion factor αμ for the mean-square electric dipole moment is studied on the basis of the helical wormlike chain with the excluded-volume effect incorporated in the Yamakawa–Stockmayer–Shimada scheme. A general expression is formulated for the first-order perturbation coefficient Kμ(L) for the chain of total contour length L. The asymptotic solution for Kμ(L) in the limit of L→∞ is evaluated analytically in the Daniels approximation by an application of the operational method. In contradiction to the common notion, it is found that, in the case of κ0τ0≠0 with κ0 and τ0 being the constant curvature and torsion, respectively, of the characteristic helix, Kμ(∞) does not vanish even for the chain having a local electric dipole moment vector perpendicular to the chain contour, indicating that αμ diverges with increasing molecular weight.