# Example: Excitation energies and polarizability: Au2¶

Download Au2_Resp.run

A calculation of response properties of the Au2 dimer, with ZORA relativistic corrections

\$ADFBIN/adf << eor
Title Au2, Response Properties

XC
GGA  LB94
End

Relativistic Scalar ZORA

Atoms
Au   0.0 0.0 1.236
Au   0.0 0.0 -1.236
End

Basis
Au ZORA/DZ/Au.4d
End

Symmetry D(8h)

Excitations
Lowest 10
TOLERANCE 1d-10
End

Response
AllComponents
End

End Input
eor


In the response module infinite symmetries cannot be handled (see the User’s Guide), so we specify a lower subgroup in the input file, here D(8h).

In this sample run the LB94 potential is used. The implementation implies that the XC potential is evaluated from the exact charge density, rather than the cheaper and faster fitted density (as is the case for other XC functionals). This means that the computation times are longer. In a small molecule like Au2 this hardly shows, but in larger molecules the differences may be more significant. Note that the LB94 is a model potential, thus the calculated bond energy has not so much meaning. If the BASIS key is used and the model potential LB94 in the create run of the atoms the BP86 functional is used.

Excitation energies are computed, in principle the lowest 10 in each irrep of the symmetry (see, however, the User’s Guide).