A new phase field variational implicit solvent model of molecular solvation with Coulomb-filed approximation
主 题: A new phase field variational implicit solvent model of molecular solvation with Coulomb-filed approximation
报告人: Prof. Yanxiang Zhao, George Washington University
时 间: 2017-07-05 16:00 - 2017-07-05 17:00
地 点: Room 29, Quan Zhai, BICMR
A phase field variational implicit-solvent approach is developed for the solvation of charged molecules. All the surface energy, the solute-solvent van der Waals interaction, and the electrostatic interaction are coupled together self-consistently through a phase field. The proposed method is different from our previous work in the sense that our new model here capture the consistency between phase field model and sharp interface model not only in the free-energy formulation but also in the corresponding Euler-Lagrange equation. By introducing a new phase field term in the long-range interaction (van der Waals interaction and electrostatic interaction), we make the variational force terms in the Euler-Lagrange equation all confined in the phase field transition layer region and no contributions in the region away from transition layer. An efficient and stable method is adopted to solve the gradient flow system to determine the equilibrium conformations and free energies of an underlying charged molecular system. Applications to single ions, a two-plate system, reveal that the new theory and methods can capture capillary evaporation in hydrophobic confinement and corresponding multiple equilibrium states as found in molecular dynamics simulations. Comparisons of the phase field and the original sharp interface variational approaches are discussed.