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want to modify NDSolve--molecular dynamics with mathematica

  • To: mathgroup at smc.vnet.net
  • Subject: [mg26304] want to modify NDSolve--molecular dynamics with mathematica
  • From: "Toshiyuki \(Toshi\) Meshii" <meshii at mech.fukui-u.ac.jp>
  • Date: Sun, 10 Dec 2000 00:20:14 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Hello,

I was wondering whether I can apply NDSolve to molecular dynamics, on the
standpoint of periodical boundary condition.

The eqation I want to solve is the simple Newton equation (Let me simplify
the problem).
  m D[x, {x,2}] == F
However, periodical boundary condition makes it difficult to apply NDSolve.
That is, once
  0<x[t]<a0
is not satisfied (a0 is a constant), I have to move the atom so that this
condition is satisfied.
In concrete,
  if x[t]<0  --->  x[t]=x[t]+a0
  if x[t]>a0  --->  x[t]=x[t]-a0
and then restart to solve the equation.

Is there any way to realize this by directly applying NDSolve?
If not, how can I modify NDSolve?

-Toshi



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