FIGURE 6.

Yukawa-segment pair potential per length L_p as a function of the interaxial separation R of two DNA molecules, at the optimal azimuthal orientation angle φ_opt (solid line, continuous line charge distribution), at the optimal angle φ_opt = (φ₁ − φ₂)_opt with the optimal combination of φ₁ and φ₂, as described in the text (dashed line, N = 10 discrete charges) and as function of φ₂ with φ₁ = 0 fixed (dotted line, N = 10 discrete charges). All interactions are for counterion condensation parameters θ = 0.9 and f₁ = 0.3, f₂ = 0.7, and f₃ = 0. The dependence of the optimal angle on the interaxial separation R is shown in the inset.