Example: TD-DFT+TB: Triplet excited state geometry optimization¶

#!/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