# Example: water molecules on a lattice
#
# This example creates a system of water molecules whose centers
# of mass are positioned simple cubic lattice consisting of
# 3x4x5 cells, i.e. there are 60 water molecules in total.
# The molecules are put into a suitably sized periodic universe.
#
from MMTK import *
from Scientific.Geometry.Objects3D import SCLattice
from MMTK.Visualization import view
# Define parameters of the lattice
edge_length = 0.5*Units.nm
lattice_size = (3, 4, 5)
# Construct the universe
universe = OrthorhombicPeriodicUniverse((edge_length*lattice_size[0],
edge_length*lattice_size[1],
edge_length*lattice_size[2]))
# Add the water molecules
for point in SCLattice(edge_length, lattice_size):
universe.addObject(Molecule('water', position = point))
# Visualization
view(universe)