I might ask a dumb question.
I was trying to use ATK DFT method to calculate the isolated hydrogen atom energy level.
But I just couldn't get it right. The calculated ground state energy level is always around -5.77eV using DFT method (-6.34eV for SK method).
I already knew that the Hydrogen atom energy level should have a ground state energy -13.6eV.
Where did I get it wrong?
(BTW, the Extend Huckel works pretty well, as I expect.)
# -------------------------------------------------------------
# Molecule configuration
# -------------------------------------------------------------
# Define elements
elements = [Hydrogen]
# Define coordinates
cartesian_coordinates = [[ 0., 0., 0.]]*Angstrom
# Set up configuration
molecule_configuration = MoleculeConfiguration(
elements=elements,
cartesian_coordinates=cartesian_coordinates
)
# -------------------------------------------------------------
# Calculator
# -------------------------------------------------------------
calculator = LCAOCalculator()
molecule_configuration.setCalculator(calculator)
nlprint(molecule_configuration)
molecule_configuration.update()
nlsave('C:/ATK/ATKstudy/Hydrogen_MO_1.nc', molecule_configuration)
# -------------------------------------------------------------
# Molecular energy spectrum
# -------------------------------------------------------------
molecular_energy_spectrum = MolecularEnergySpectrum(
configuration=molecule_configuration,
energy_zero_parameter=AbsoluteEnergy,
projection_list=ProjectionList(elements=[Hydrogen], angular_momenta=[0, 1, 2, 3])
)
nlsave('C:/ATK/ATKstudy/Hydrogen_MO_1.nc', molecular_energy_spectrum)
nlprint(molecular_energy_spectrum)