Radial Manning parameter

Figure 23 The radial Manning parameter (r) (top frame, cell model only Eq. [244]) and potential c )(r) (bottom frame Eq. [245]) in the PB cell and bulk models for a charged cylinder of radius <3 = 10 A and surface charge density = —0.094 e(jk (corresponding to an average charge spacing of h = 1.69 A as in B-DNA). A site concentration (corresponding to a phosphate concentration in DNA) of 0.1 M has been chosen, giving a Manning radius of Rm = 29.6 A and a cell radius of R = 56 A. The PB cell model potential profile (solid lines) is compared to the bulk PB (dotted-dashed line Eq. [389]), DH cell model (dashed lines Eq. [256]), DH bulk model (dotted line Eq. [259]), and no-ion (circles Eq. [362]) values.

FIG. 16 Ion distribution function P(r) (left) and mean electrostatic potential if/j) (right) for DNA-like systems (see Table 1) with 0.5 mol/L added 2 2 salt. The six curves differ in the line charge density of the rod, producing Manning parameters between 1.05 and 10.5 as indicated in the key. The value 4.2 corresponds to DNA. Notice that the radial distance is only plotted up to one third of the cell radius. 

On a sufficiently short length scale, the polyion can thus be considered to be linear (Fig. 4). The radial distribution of the dissociated counterions around such a linear charged chain can be computed by a Poisson-Boltzmann approach." The dielectric permittivity of the solvent as well as temperature can be considered by an electrostatic screening length called the Bjerrum length Ib. The electrostatic potential of the polyion is then described by the Manning parameter where b is... 

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