Example: Numerical Frequencies, spin-orbit coupled ZORA: UF6¶
- Geometry optimization
- Frequencies with symmetric displacements
- Both for scalar relativistic ZORA and spin-orbit coupled ZORA
Here only the spin-orbit coupled input file for ADF is given (in the scalar relativistic case change “spinorbit” in “scalar”). The resulting TAPE21 is saved such that it can be used in the frequency calculation.
$ADFBIN/adf <<eor Title UF6 geometry optimization: scalar ZORA BeckeGrid Quality good End Geometry conv grad=1e-4 End relativistic spinorbit zora Basis Type TZP end ATOMS cartesian 1 U .00000 .00000 .00000 2 F 2.00000 .00000 .00000 3 F -2.00000 .00000 .00000 4 F .00000 2.0000 .00000 5 F .00000 -2.0000 .00000 6 F .00000 .0000 2.00000 7 F .00000 .0000 -2.00000 END end input eor mv TAPE21 UF6.t21
Frequencies with symmetric displacements
Computation of frequencies by symmetric displacements. The assumed equilibrium input structure should be given in Cartesian coordinates. The calculation starts with the optimized structure read from UF6.t21 (restart file). Again only the spin-orbit coupled input file for ADF is given.
The symmetry is determined automatically by the program as O(H), from the input coordinates. During the calculation first symmetric atomic displacements are constructed. The number of such displacements in each irreducible representation corresponds to the number of frequencies with the corresponding symmetry. All displaced geometries within one representation have the same symmetry, which enables us to use it to speed up the computation significantly.
In case of spin-orbit coupling the frequencies can not (yet) be calculated with analytical second derivatives.
$ADFBIN/adf <<eor Title UF6 frequencies and IR intensities: spinorbit ZORA Restart UF6.t21 Geometry Frequencies Symm End BeckeGrid Quality good End relativistic spinorbit zora Fragments U t21.U F t21.F end ATOMS cartesian 1 U .00000 .00000 .00000 2 F 2.00000 .00000 .00000 3 F -2.00000 .00000 .00000 4 F .00000 2.0000 .00000 5 F .00000 -2.0000 .00000 6 F .00000 .0000 2.00000 7 F .00000 .0000 -2.00000 END end input eor