Example: CD spectrum, hybrid functional: Twisted ethene¶

#!/bin/sh 


# If the subkey CDSPECTRUM is included in the key EXCITATIONS, the rotatory
# strength is calculated for the calculated excitations, in order to calculate
# the CD (Circular Dichroism) spectrum. Only useful for chiral molecules. A
# hybrid functional is used in this case.

# With the VELOCITY keyword also the dipole-velocity representation of the
# rotatory strength is calculated.

# Note: results will be physically meaningless due to small basis set. purpose
# of this job is to provide a test case for the CD implementation

# Do not use less strict convergence criteria than default, better to use
# tighter criteria. The approximations in the evaluation of the integrals one
# makes with the linear scaling techniques are effectively switched off by
# setting LINEARSCALING 99 (recommended to use this).

$AMSBIN/ams <<eor
System
  symmetrize
  atoms
     C 0.000000 0.000000 0.000000
     C -0.000000 -0.000000 1.350716
     H 0.565703 -0.745428 -0.540179
     H -0.565703 0.745428 -0.540179
     H 0.035837 -0.935093 1.890895
     H -0.035837 0.935093 1.890895
  end
end

Task SinglePoint

Engine ADF
  title twisted ethene
  comment
     purpose of this job is to provide a test case for the CD implementation
     with hybrid functionals, and to test the "velocity" keyword
  end
  excitations
    cdspectrum
    lowest 20
    onlysing
    velocity
  end
  linearscaling 99
  end
  basis
    core Small
    type TZ2P
  end
  numericalquality good
  rihartreefock
    fitsetquality Normal
  end
  scf
    converge 1.e-8
  end
  xc
    hybrid PBE0
  end
  Relativity
    Level None
  End
EndEngine

eor