Linear response of a grafted semiflexible polymer to a uniform force field

We use the wormlike chain model to analytically calculate the linear response of a grafted semiflexible polymer to a uniform force field. The result is a function of the bending stiffness, the temperature, the total contour length, and the orientation of the field with respect to that of the grafted end. We also study the linear response of a wormlike chain with a periodic alternating sequence of positive and negative charges. This can be considered as a model for a polyampholyte with intrinsic bending stiffness and negligible intramolecular interactions. We show how the finite intrinsic persistence length affects the linear response to the external field.