APPROXIMATIVE ANALYTICAL SOLUTIONS OF THE POISSON-BOLTZMANN EQUATION FOR CHARGED RODS IN THE PRESENCE OF SALT - AN ANALYSIS OF THE CYLINDRICAL CELL MODEL

Current analytical approximations to the solution of the Poisson-Boltz mann (PB) equation in cylindrical symmetry and in the presence of salt are compared with the corresponding numerical solution of this equati on. Two new analytical solutions are presented. One has been developed from the exact analytical solution of the PB equation without salt, w hereas the other has been derived as an extension of the solution of t he linearized PB equation in the case of excess added salt. For all PB solutions presented the zero point of the electrostatic potential is fixed in the external solution. An analytical expression has been deri ved which relates the salt concentration of this reference solution to that of the rod-containing cell. (C) 1995 Academic Press, Inc.