科研之友
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摘要
The dielectric polarization P is the key factor for computing electromagnetic interactions between charged particles in materials in classical electrodynamics, and for computing hydration free energy of biomolecules in the field of physical chemistry. Near-solute P dominates electric contributions to the solute from polarized solvent media and oscillates with decay according to the distance to the solute. This oscillating decay is observed in molecular dynamics simulations and cannot be reproduced from Gauss's law of Maxwell's equations. In the present paper, P was decomposed into the electric dipole moment p and the solvent density rho. Equations and an approximate analytical solution capturing the oscillating decay of p were derived for a spherical solute. The equations can be used to understand physically why p oscillates according to the distance to the solute. The approximate analytical solution can identify factors, such as the solvent molecular radius R-W and the solvent molecular electric susceptibility X-e(g), changing the amplitude and the oscillation period of p. In addition, the approximate analytical solution of p is similar to the solution of a spring system with harmonic damping. However, the equation describing p uses a first-order integral equation and thus differs from the equation describing a spring system which uses a second-order differential equation.
- 出版日期2011-1-15
