• Title/Summary/Keyword: Poission-Boltzmann

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Calculation of the Solvation Free Energy of the Proton in Methanol

  • Hwang, Sun-Gu;Chung, Doo-Soo
    • Bulletin of the Korean Chemical Society
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    • v.26 no.4
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    • pp.589-593
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    • 2005
  • The solvation free energy of proton in methanol was calculated by B3LYP flavor of density functional calculations in combination with the Poisson-Boltzmann continuum solvation model. In order to check the adequacy of the computation level, the free energies of clustering in the gas phase were compared with the experimental data. The solvents were taken into account in a hybrid manner, i.e. one to five molecules of methanol were explicitly considered while other solvent molecules were represented with an implicit solvation model.

Electrical Repulsive Energy between Two Cylindrical Particles with Finite Length: Configuration Dependence

  • Choi, Ju-Young;Dong, Hyun-Bae;Haam, Seung-Joo;Lee, Sang-Yup
    • Bulletin of the Korean Chemical Society
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    • v.29 no.6
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    • pp.1131-1136
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    • 2008
  • The electrical repulsive energy between two model cylinders was calculated by solving nonlinear Poission- Boltzmann (P-B) equation under Derjaguin approximation. Effects of the surface potential, Debye screening length, and configuration of cylinders on the repulsive interaction energy were examined. Due to the anisotropy of the shape of cylinder, the interaction repulsive energy showed dependence to the configuration of particles; cylinders aligned in end-to-end configuration showed largest repulsive energy and crossed particles had lowest interaction energy. The configuration effect is originated from the curvature effect of the interacting surfaces. The curved surfaces showed less repulsive energy than flat surfaces at the same interacting surface area. The configuration dependency of interaction energy agreed with the previous analytical solution obtained under the linearized P-B equation. The approach and results present in this report would be applicable in predicting colloidal behavior of cylindrical particles.

Effects of the Counter Ion Valency on the Colloidal Interaction between Two Cylindrical Particles

  • Lee, In-Ho;Dong, Hyun-Bae;Choi, Ju-Young;Lee, Sang-Yup
    • Bulletin of the Korean Chemical Society
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    • v.30 no.3
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    • pp.567-572
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    • 2009
  • In this study, the effects of counter ion valency of the electrolyte on the colloidal repulsion between two parallel cylindrical particles were investigated. Electrostatic interactions of the cylindrical particles were calculated with the variation of counter ion valency. To calculate the electrical repulsive energy working between these two cylindrical particles, Derjaguin approximation was applied. The electrostatic potential profiles were obtained numerically by solving nonlinear Poission-Boltzmann (P-B) equation and calculating middle point potential and repulsive energy working between interacting surfaces. The electrical potential and repulsive energy were influenced by counter ion valency, Debye length, and surface potential. The potential profile and middle point potential decayed with the counter ion valency due to the promoted shielding of electrical charge. On the while, the repulsive energy increased with the counter ion valency at a short separation distance. These behaviors of electrostatic interaction agreed with previous results on planar or spherical surfaces.