This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: I This introduced charge distribution screens the interaction between neighboring point-charges limiting them to a short range I Consequently, the sum converges rapidly I To counteract this Gaussian distribution, a second Gaussian distribution of the same sign as magnitude as the original distribution is added for each point charge I Now, the summation is carried out in reciprocal space using Fourier transforms I For a system with charges, also the surrounding medium has an effect: in a perfect conductor ( ε = ∞ ), the Ewald summation works I However, if the system is in vacuum ( ε = 1 ), a dipole layer should form at the surface I This can be taken into account by adding a dipole term in the summation I The dipole term includes the effects of the total dipole moment of the unit cell, the shape of the macroscopic lattice, and the dielectric constant of the surrounding medium I Overall, the final outcome of the potential becomes rather complicated, but luckily ready-made programs exist for Ewald summation [Anastasiou & Fincham, Comput. Phys. Commun. 25, 159 (1981)] I...
View Full Document
This note was uploaded on 02/14/2012 for the course CSE 6590 taught by Professor Kotakoski during the Winter '12 term at York University.
- Winter '12