Example: Excitation energies perturbative spin-orbit coupling: AgI¶

#! /bin/sh


# Calculation of the excitation energies of AgI including spin-orbit coupling in
# a perturbative way.

# ADF can not handle ATOM and linear symmetries in excitation calculations.
# In case of linear symmetries ADF will automatically use a 
# a subsymmetry, in this case symmetry C(7v).
# In the excitation part of the output the symmetry labels are those of C(LIN) in this case.

# For such a small molecule, a relatively small TZ2P basis set is used, which is
# not sufficient for excitations to Rydberg-like orbitals, one needs more
# diffuse functions. For larger molecules a TZ2P basis set is in most cases
# sufficient. In that case one might even consider smaller basis sets.

# The key SOPERT is included in scalar relativistic ZORA calculations of
# excitation energies. First scalar relativistic TDDFT calculations are
# performed to determine the lowest 60 singlet-singlet and singlet-triplet
# excited states and the spin-orbit coupling operator is applied to these
# single-group excited states to obtain the excitation energies with spin-orbit
# coupling effects included.


$AMSBIN/ams <<eor
System
  atoms
     Ag 0.0000  0.0000  2.5446
     I  0.0000  0.0000  0.0000
  end
end

Task SinglePoint

Engine ADF
  title [AgI]
  excitations
    lowest 60
  end
  basis
    type TZ2P
    core None
    CreateOutput Yes
  end
  numericalquality Good
  sopert
  end
EndEngine

eor