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

Download TiCl4_XASXES.run

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.

$ADFBIN/adf << eor TITLE TiCl4 X-Ray Absorption and Emission Quadrupole Oscillator strengths at the Cl K-edge ATOMS 1 Ti 0.0000 0.0000 0.0000 2 Cl 0.0000 0.0000 2.2930 3 Cl.1 1.0809 -1.8722 -0.7643 4 Cl.1 -2.1618 0.0000 -0.7643 5 Cl.1 1.0809 1.8722 -0.7643 END SYMMETRY C(3V) BASIS type TZP core None createoutput None Cl.1$ADFRESOURCES/TZP/Cl.2p
END

XC
GGA Becke Perdew
END

EPRINT
eigval 1000 1000
orbpoper -10000 100
End

RELATIVISTIC Scalar ZORA

XES
COREHOLE A1 2
END

MODIFYEXCITATION
UseOccupied
A1 2
SubEnd
END

EXCITATION
Davidson
ONLYSING
lowest 10
XAS
END

end input
eor


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

ATOMS
1  Ti              0.0000    0.0000    100.0000
2  Cl              0.0000    0.0000    102.2930
3  Cl.1            1.0809   -1.8722     99.2357
4  Cl.1           -2.1618    0.0000     99.2357
5  Cl.1            1.0809    1.8722     99.2357
END