Exact results for a semiflexible polymer chain in an aligning field

We provide exact results for the Laplace-transformed partition function of a wormlike chain subject to a tensile force and in a nematic field, in both two and three dimensions. The results are in the form of infinite continued fractions, which are obtained by exploiting the hierarchical structure of a moment-based expansion of the partition function. The case of an imaginary force corresponds to the end-to-end distance distribution in Laplace - Fourier space. We illustrate the utility of these exact results by examining the structure factor of a wormlike chain, the deformation free energy of a chain in a nematic field, and the self-consistent-field solution for the isotropic - nematic transition of wormlike chains.