# Set up a configuration.
molecule_configuration = MoleculeConfiguration(
    elements=[Nitrogen, Hydrogen, Hydrogen, Hydrogen],
    cartesian_coordinates=[[ 0.     ,  0.      ,  0.124001],
                           [ 0.     ,  0.941173, -0.289336],
                           [ 0.81508, -0.470587, -0.289336],
                           [-0.81508, -0.470587, -0.289336]]*Angstrom
    )

# Define a calculator.
calculator = LCAOCalculator()
molecule_configuration.setCalculator(calculator)

# Calculate and save the Hartree difference potential.
potential = HartreeDifferencePotential(molecule_configuration)
nlsave('hartree_difference_pot.nc', potential)