from ATK.KohnSham import *

# Create Bravais lattice 
lattice_constant = 5.43*Angstrom
fcc_lattice = FaceCenteredCubic(lattice_constant)

# Specify bulk configuration with 2 silicon atoms
# as basis in a FCC Bravais lattice
si_fcc = BulkConfiguration(
    bravais_lattice = fcc_lattice,
    elements = 2*[Silicon],
    fractional_coordinates = [
        [0.00, 0.00, 0.00], 
        [0.25, 0.25, 0.25]
        ]
    )

# Display Cartesian coordinates for silicon crystal
from printBulkConfig import printBulkConfig
printBulkConfig(si_fcc)

# Store crystal structure in a VNL file for later use
vnl_file=VNLFile("si.vnl")
vnl_file.addToSample(si_fcc,"si_fcc")