Xueyu Song

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  Beyond Poisson-Boltzmann approach in macromolecules electrostatics
  Xueyu Song
  In this presentation a molecular Debye-Huckel theory for ionic fluids is developed. Starting from the macroscopic Maxwell equations for bulk systems, the dispersion relation leads to a generalized Debye-Huckel theory which is related to the dressed ion theory in the static case.Due to the multi-pole structure of the dielectric function of ionic fluids, the electric potential around a single solute has a multi-Yukawa form. Given the dielectric function, the multi-Yukawa potential can be determined from our molecular Debye-Huckel theory, hence, the electrostatic contributions to thermodynamic properties of ionic fluids can be obtained. Applications to solutes with arbitrary shapes in model electrolyte solutions demonstrated the accuracy of our approach. In combination with cavity formation energy a variational approach can be used to define the boundary between a solute and its continuum solvent. Thus, our approach provides a simple and efficient path to go beyond the traditional Poisson-Boltzmann model in biophysics.