# Set up 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 the calculator
calculator = HuckelCalculator()
molecule_configuration.setCalculator(calculator)

# Calculate and save the molecular energy spectrum
molecular_energy_spectrum = MolecularEnergySpectrum(
    configuration=molecule_configuration,
    energy_zero_parameter=AbsoluteEnergy,
    projection_list=ProjectionList(elements=[Nitrogen], angular_momenta = [0])
    )
nlsave('molecular.hdf5', molecular_energy_spectrum)

# Extract the energy
energy = molecular_energy_spectrum.evaluate()
occ = molecular_energy_spectrum.occupation()

# ... and print it out
print("level   energy(eV)    occupation")
for i in range(len(energy[0])):
    print('  %d  %12.4f  %12.4f  ' % (i, energy[0][i].inUnitsOf(eV),occ[0][i]))