Example: X-Ray Absorption and Emission Quadrupole Oscillator strengths at the Cl K-edge: TiCl4¶

#! /bin/sh


# Calculation of the 1s Cl core excitation energies of TiCl4. Both X-Ray
# Emission (XES keyword) and X-Ray absorption (XAS keyword in EXCITATION key)
# are calculated. The individual (zeroth and higher order) oscillator strength
# components to the total oscillator strengths will be printed
# (ALLXESQUADRUPOLE, ALLXASQUADRUPOLE).

# In order to calculate a 1s-orbital that is localized on one of the Cl atoms, a
# frozen core approach is used on the other Cl atoms, such that there is only
# one Cl 1s-orbital, which will remain localized in the molecule.

# In order to get information of the population analysis on all core orbitals, a
# large negative value was included as argument for the orbpoper subkey of the
# block key EPRINT. This orbital analysis shows that the 2 A1 orbital is indeed
# the 1s Cl orbital, see subkey corehole of block key XES, and subkey
# useoccupied of block key MODIFYEXCITATION.

AMS_JOBNAME=XASXES $AMSBIN/ams <<eor
System
  symmetrize
  atoms
     Ti   0.0000    0.0000    0.0000
     Cl   0.0000    0.0000    2.2930
     Cl   1.0809   -1.8722   -0.7643   region=Cl.2p
     Cl  -2.1618    0.0000   -0.7643   region=Cl.2p
     Cl   1.0809    1.8722   -0.7643   region=Cl.2p
  end
end

Task SinglePoint

Engine ADF
  title TiCl4 X-Ray Absorption and Emission Quadrupole Oscillator strengths at the Cl K-edge
  eprint
    eigval 1000 1000
    orbpoper -10000 100
  end
  excitations
    allxasquadrupole
    davidson
    end
    lowest 10
    onlysing
    xas
  end
  modifyexcitation
    useoccupied
       A1 2
    end
  end
  basis
    PerRegion Region=Cl.2p File=$AMSRESOURCES/ADF/TZP/Cl.2p
    core None
    type TZP
  end
  relativity
    level scalar
    formalism ZORA
  end
  scf
    iterations 200
  end
  symmetry C(3V)
  xc
    gga Becke Perdew
  end
  xes
    allxesquadrupole
    corehole A1 2
  end
EndEngine

eor


# In the second example, to test gauge dependency, the molecule is shifted 100
# Angstrom in the z-direction.

AMS_JOBNAME=Gauge $AMSBIN/ams <<eor
System
  symmetrize
  atoms
     Ti   0.0000    0.0000    100.0000
     Cl   0.0000    0.0000    102.2930
     Cl   1.0809   -1.8722     99.2357   region=Cl.2p
     Cl  -2.1618    0.0000     99.2357   region=Cl.2p
     Cl   1.0809    1.8722     99.2357   region=Cl.2p
  end
end

Task SinglePoint

EngineRestart XASXES.results/adf.rkf

Engine ADF
  title TiCl4 X-Ray Absorption and Emission Quadrupole Oscillator strengths at the Cl K-edge shifted 100Ang in z-direction
  eprint
    eigval 1000 1000
    orbpoper -10000 100
  end
  excitations
    allxasquadrupole
    davidson
    end
    lowest 10
    onlysing
    xas
  end
  modifyexcitation
    useoccupied
       A1 2
    end
  end
  basis
    PerRegion Region=Cl.2p File=$AMSRESOURCES/ADF/TZP/Cl.2p
    core None
    type TZP
  end
  relativity
    level scalar
    formalism ZORA
  end
  scf
    iterations 200
  end
  symmetry C(3V)
  xc
    gga Becke Perdew
  end
  xes
    allxesquadrupole
    corehole A1 2
  end
EndEngine

eor