Example: unrestricted fragments: CH3I¶

#!/bin/sh


# An illustration of an unrestricted energy decomposition analysis (unrestricted EDA).

# Prepared for bonding
# --------------------

# The electron configuration of the fragments is chosen such that the valence I p_z orbital
# has 1 alpha electron, and the highest occupied Methyl orbital has 1 beta electron.
# Note that this electron configuration of the fragments means that they
# are so called 'prepared for bonding' in order to minimize the Pauli repulsion in
# the electron pair bond.

AMS_JOBNAME=I_A $AMSBIN/ams <<eor
System
  atoms
     I  0.0 0.0 0.0
  end
end

Task SinglePoint

Engine ADF
  irrepoccupations
     Sigma.g 2 // 2
     Sigma.u 1 // 0
     Pi.g    2 // 2
     Pi.u    2 // 2
     Delta.g 2 // 2
  end
  basis
    core Small
    type TZ2P
  end
  numericalquality good
  relativity
    level scalar
    formalism ZORA
  end
  spinpolarization 1
  symmetry D(lin)
  unrestricted
  xc
    gga BP86
  end
EndEngine

eor


AMS_JOBNAME=Methyl_B $AMSBIN/ams <<eor
System
  atoms
     C       0.000000000000       0.000000000000      -0.239316000000
     H      -0.521322100000      -0.902956360000      -0.562716000000
     H      -0.521322100000       0.902956360000      -0.562716000000
     H       1.042644200000      -0.000000000000      -0.562716000000
  end
end

Task SinglePoint

Engine ADF
  basis
    core Small
    type TZ2P
  end
  numericalquality good
  relativity
    level scalar
    formalism ZORA
  end
  spinpolarization -1
  unrestricted
  xc
    gga BP86
  end
EndEngine

eor

# The fragments are prepared. Next the unrestricted EDA is performed,
# in which symmetry can be used.

AMS_JOBNAME=ch3i $AMSBIN/ams <<eor
System
  atoms
     C       0.000000000000       0.000000000000      -0.239316000000  adf.f=Methyl_B
     H      -0.521322100000      -0.902956360000      -0.562716000000  adf.f=Methyl_B
     H      -0.521322100000       0.902956360000      -0.562716000000  adf.f=Methyl_B
     H       1.042644200000      -0.000000000000      -0.562716000000  adf.f=Methyl_B
     I       0.000000000000       0.000000000000       1.927464000000  adf.f=I_A
  end
end

Task SinglePoint

Engine ADF
  fragments
     I_A I_A.results/adf.rkf
     Methyl_B Methyl_B.results/adf.rkf
  end
  numericalquality good
  relativity
    level scalar
    formalism ZORA
  end
  spinpolarization 0
  unrestricted
  unrestrictedfragments
  xc
    gga BP86
  end
EndEngine

eor

# Same calculation but now using ETS-NOCV.
# ETS-NOCV: energy analysis using the Natural Orbitals for Chemical Valence.
# In ETS-NOCV symmetry NOSYM is required.

AMS_JOBNAME=etsnocv $AMSBIN/ams <<eor
System
  atoms
     C       0.000000000000       0.000000000000      -0.239316000000  adf.f=Methyl_B
     H      -0.521322100000      -0.902956360000      -0.562716000000  adf.f=Methyl_B
     H      -0.521322100000       0.902956360000      -0.562716000000  adf.f=Methyl_B
     H       1.042644200000      -0.000000000000      -0.562716000000  adf.f=Methyl_B
     I       0.000000000000       0.000000000000       1.927464000000  adf.f=I_A
  end
end

Task SinglePoint

Engine ADF
  etsnocv
  end
  fragments
     I_A I_A.results/adf.rkf
     Methyl_B Methyl_B.results/adf.rkf
  end
  numericalquality good
  relativity
    level scalar
    formalism ZORA
  end
  spinpolarization 0
  symmetry nosym
  unrestricted
  unrestrictedfragments
  xc
    gga BP86
  end
EndEngine

eor