From: Jérôme Hénin (jerome.henin_at_uhp-nancy.fr)
Date: Fri Mar 11 2005 - 15:31:47 CST
Le vendredi 11 Mars 2005 20:15, Marc Q. Ma a écrit :
> Ed,
>
> > There is a physical justification for using PBC, PBC conserve the
> > momentum of the system. It is my understanding that without PBC
> > conservation of momentum is violated.
> >
> > Ed
>
> For conservative systems, conservation of momentum has nothing to do
> with boundary conditions. For MD as is row, the forces are all pairwise
> additive, and F12 = -F21. Momentum is strictly conserved.
Unless of course you use PME. Because of the grid interpolation of the charge
distribution, which is an approximation, PME does not strictly conserve
momentum.
Jerome
-- Jérôme Hénin Equipe de Dynamique des Assemblages Membranaires Université Henri Poincaré / CNRS Tel : (33) 3 83 68 43 95 Fax : (33) 3 83 68 43 71 http://www.edam.uhp-nancy.fr/
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