From: Marc Q. Ma (qma_at_oak.njit.edu)
Date: Fri Mar 11 2005 - 13:15:31 CST
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. I am not sure
about polarizable force fields, I guesstimate it is still true.
When there is random force, such as the Langevin Pistons or heat
reservoirs, the momentum conservation is going to be violated at each
time step.
Marc
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