Figure 4.

Effective dielectric constant for solvated phosphate–phosphate repulsions in linear (top) and bent (bottom) DNA. Red points are intra-strand repulsions, blue points are inter-strand repulsions. See Equations 4 and 5 for the definitions of ε′ and R′. Data beyond 30 Å are not shown to better illustrate the deviations at short range; beyond 30 Å the ε′ values are all very close to that of bulk water (ε = 80).