Example: NOCV: CH3 – CH3

Download CH3_CH3_etsnocv.run

#! /bin/sh


# Example for calculation of ETS-NOCV for simulated unrestricted fragments. ETS-NOCV:
# energy analysis using the Natural Orbitals for Chemical Valence. The ethane
# molecule is built from two methyl radicals

# First the two methyl fragments are calculated.
# If  the FRAGOCCUPATIONS keyword is used in ethane the fragments should be calculated
# spin-restricted.


$ADFBIN/adf <<eor
  Title CH3-CH3 built from CH3 radicals,  FULL electron calc.!
  atoms cartesian
    C         0.019664   -0.034069    0.009101 
    H         0.039672   -0.069395    1.109620 
    H         1.063205   -0.065727   -0.341092 
    H        -0.474230   -0.953693   -0.341621 
  end
  basis
    H  $ADFRESOURCES/DZP/H
    C  $ADFRESOURCES/DZP/C
  end
  symmetry NOSYM
  SCF
    Iterations 2500
    Converge 1E-6
  end
  xc
    gga becke perdew
  end
eor
mv TAPE21 t21.frag1

$ADFBIN/adf <<eor
  Title CH3 radical
  atoms cartesian
    C        -0.703210    1.217999   -0.497874 
    H        -0.723753    1.252869   -1.598316 
    H        -1.746567    1.250049   -0.147169 
    H        -0.208833    2.137544   -0.147653 
  end
  basis
    H  $ADFRESOURCES/DZP/H
    C  $ADFRESOURCES/DZP/C
  end
  symmetry NOSYM
  SCF
    Iterations 2500
    Converge 1E-6
  end
  xc
    gga becke perdew
  end
eor
mv TAPE21 t21.frag2

# Next these fragments are used in the calculation of the molecule ethane, using
# the key FRAGOCCUPATIONS to use an unrestricted fragment occupation for the
# methyl radicals, such that they are prepared for bonding. In the one fragment
# the singly occupied orbital will be an alpha-orbital, and in the other fragment
# the singly occupied orbital will be a beta-orbital, such that the calculated
# Pauli repulsion between the fragments will be small.

# The block key ETSNOCV used here is in its single line form.
# The symmetry must be NOSYM.

$ADFBIN/adf <<eor
  Title final [CH3]-[CH3], etsnocv activated by etsnocv
  atoms
    C         0.019664   -0.034069    0.009101 f=f1
    H         0.039672   -0.069395    1.109620 f=f1
    H         1.063205   -0.065727   -0.341092 f=f1
    H        -0.474230   -0.953693   -0.341621 f=f1
    C        -0.703210    1.217999   -0.497874 f=f2
    H        -0.723753    1.252869   -1.598316 f=f2
    H        -1.746567    1.250049   -0.147169 f=f2
    H        -0.208833    2.137544   -0.147653 f=f2
  end
  fragments
    f1 t21.frag1
    f2 t21.frag2
  end
  fragoccupations
    f1
      A 5 // 4 
    subend
    f2
      A 4 // 5 
    subend
  end
  symmetry NOSYM
  SCF
    Iterations 800
    Converge 1E-6
  end
  xc
    gga becke perdew
  end
  ETSNOCV RHOKMIN=1.e-3 EKMIN=1.5 ENOCV=0.05
eor

# Next densf calculations, to view the natural orbitals in this method, see
# also the the documentation for the densf analysis program and the ADF-GUI.
# Input is the TAPE21 of the molecular calculation.

$ADFBIN/densf <<eor
  Grid Medium
  End
  NOCV
   Alpha
     1
     2
     59
     60
   Beta
     1
     2
     59
     60
  END
eor
mv TAPE41 nocv1.t41

$ADFBIN/densf <<eor
  Grid Medium
  End
  NOCV
    THRESH 0.01
    RESTSUM
  END
eor
mv TAPE41 nocv2.t41

$ADFBIN/densf <<eor
  Grid Medium
  End
  NOCV
    ALPHA
      SUM 1
    BETA
      SUM 1
    RESTSUM
  END
eor
mv TAPE41 nocv3.t41

$ADFBIN/densf <<eor
  Grid Medium
  End
  NOCV
    SUMBELOW 0.5
  END
eor
mv TAPE41 nocv4.t41