ABSTRACT
Numerical determination of the net charge gives us a boundary between the ion atmosphere and the bulk salt solution, whereas analytical theories do not yield a clear boundary between them. According to the fluctuation–dissipation theorem, the electric polarizability of polyelectrolytes is related to the fluctuations of the dipole moment, which is spontaneously generated in the ion atmosphere around the polyions in the absence of an applied electric field. The Monte Carlo method was applied to calculate small ion distributions, electric potentials, and fluctuations of ion atmosphere polarization. In salt solutions, the contribution of coions to the electroneutrality condition must be taken into account. Stronger salt concentration dependence is, however, observed in the experiment, i.e., the induced dipole moment of deoxyribonucleic acid is inversely proportional to the square root of the ionic strength of the solution tending to zero at infinite salt concentration.
