Figure 1.
A sketch of the horizontal projection of a hexagonal aggregate of helical molecules. Shaded circles represent molecular backbones. All molecules are similar. Positive and negative charges, for simplicity shown only around the central molecule, are intrinsic surface charges, counter-ions, or fractional water charges. We assume that all essential charges are located within cylindrical shells shown by the dashed lines and neglect possible effects of charges, which may be located in interstices between the shells (a sample interstice is painted black). The thin solid circle with the radius a shows the radial center of mass of all charges associated with the central helix. The two-dimensional radius vectors R1 and R2 point from the coordinate origin to the central axes of the molecules 1 and 2, respectively, R = R2 − R1.