1 from math import cos, sin, pi
   2 
   3 from ASE import ListOfAtoms, Atom
   4 from ASE.Visualization.RasMol import RasMol
   5 from ASE.Dynamics.ConjugateGradient import ConjugateGradient
   6 from ASE.Trajectories import NetCDFTrajectory
   7 from Dacapo import Dacapo
   8 
   9 
  10 d = 2.0
  11 r = 0.9575
  12 t = pi / 180 * 104.51
  13 dimer = ListOfAtoms([Atom('O', (0, 0, 0)),
  14                      Atom('H', (-r * cos(t / 2), r * sin(t / 2), 0)),
  15                      Atom('H', (-r * cos(t / 2), -r * sin(t / 2), 0)),
  16                      Atom('O', (d + r, 0, 0)),
  17                      Atom('H', (d, 0, 0)),
  18                      Atom('H', (d + r - r * cos(t), 0, r * sin(t)))],
  19                     cell=(9, 6, 7))
  20 dimer.SetCartesianPositions(dimer.GetCartesianPositions() + (4, 3, 3.5))
  21 plot = RasMol(dimer, (2, 2, 2))
  22 calc = Dacapo(nbands=12,
  23               planewavecutoff=340,
  24               densitycutoff=500,
  25               out='2H2O.nc')
  26 calc.StayAliveOff()
  27 dimer.SetCalculator(calc)
  28 traj = NetCDFTrajectory('2H2O.traj', dimer)
  29 cg = ConjugateGradient(dimer, fmax=0.05)
  30 
  31 cg.Attach(traj)
  32 cg.Attach(plot)
  33 cg.Converge()