Example: TD-DFT+TB: Triplet excited state geometry optimization
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"Download EGO_TD-DFTB_triplet.run"

   #!/bin/sh


   # Excited state geometry optimization using TD-DFT+TB, for the molecule p-Benzoquinone.
   # The triplet excited state T3 is optimized.
   # This method is meant for GGA or LDA functionals. In this example PBE
   # is used during the SCF. In the the calculation of the excitation energies the
   # TD-DFTB+TB method is used in which the required integrals are approximated in
   # the same way as in a TD-DFTB calculation. Symmetry NOSYM is required.
   # For excited state gradients all electron basis sets are required.

   # Note that for symmetric systems, one could perturb the coordinates
   # to break the symmetry of the system. This can be done, for example,
   # by including PerturbCoordinates 0.05 in the System block.
   # In this example this is not done, which in practice means that the
   # molecule remains symmetric.

   $AMSBIN/ams <<eor
   System
     atoms
           C    0.00000000    -0.67337000     1.26921000
           C    0.00000000     0.67337000     1.26921000
           C    0.00000000     1.44457000     0.00000000
           C    0.00000000     0.67337000    -1.26921000
           C    0.00000000    -0.67337000    -1.26921000
           C    0.00000000    -1.44457000     0.00000000
           O    0.00000000     2.67997000     0.00000000
           O    0.00000000    -2.67997000     0.00000000
           H    0.00000000     1.26436000    -2.18667000
           H    0.00000000    -1.26436000    -2.18667000
           H    0.00000000     1.26436000     2.18667000
           H    0.00000000    -1.26436000     2.18667000
     end
   end

   Task GeometryOptimization

   Engine ADF
     excitations
       onlytrip
       td-dftb
     end
     basis
       core none
     end
     symmetry NOSYM
     xc
       gga PBE
     end
     excitedGO
       triplet
       state A 3
     end
   EndEngine
   eor
