Example: NOCV: ethylene – Ni-diimina and H+ – CO

Download Diimina_NOCV.run and Hplus_CO_etsnocv.run and

Example for calculation of ETS-NOCV for spin-restricted fragments. ETS-NOCV: energy analysis using the Natural Orbitals for Chemical Valence. The ethylene molecule and a Ni-diimina form a complex together. This example will be discussed first. The other example is H⁺ and CO form together HCO⁺ , this example is similar to the discussed example. All electron basis sets are required.

First the two fragments are calculated.

$ADFBIN/adf << eor
Title: et-----Ni-diimina: ethylene run

atoms cartesian
C   -0.430177075 -1.815433265  0.860288229
C   -0.363705637 -1.910722338 -0.515633302
H    0.533109934 -2.284970854 -1.016904201
H   -1.279922499 -1.884673940 -1.115144723
H   -1.389295819 -1.753589602  1.377541080
H    0.440296224 -2.041861443  1.484489314
end
basis
 Type DZP
 Core Small
end
symmetry NOSYM
xc
 gga scf becke perdew
end
endinput
eor
mv TAPE21 t21.etfrag


$ADFBIN/adf << eor
Title: et-----Ni-diimina: Ni-diimina run

atoms cartesian
Ni   0.022615419  0.037783871  0.025751533
N    0.386170317  1.871072585  0.306265538
C    1.612863056  2.248007643  0.148716016
C    2.540686607  1.163409862 -0.183603690
N    1.976290003  0.008161589 -0.301176178
H   -0.288333328  2.609667211  0.546869047
H    1.942601454  3.283060847  0.269249237
H    3.613259273  1.338293482 -0.302134814
H    2.621707427 -0.766258151 -0.517479818
H   -1.351756655  0.253389698  0.386197419
end
charge 1
basis
 Type DZP
 Core Small
end
symmetry NOSYM
xc
  gga scf becke perdew
end
endinput
eor
mv TAPE21 t21.Nifrag

Next these fragments are used in the calculation of the full complex. The keys ETSNOCV and ‘PRINT etslowdin’ are needed in this case to to analyze the bonding in the molecule with respect to the fragments. The symmetry must be NOSYM.

$ADFBIN/adf << eor
Title: et-----Ni-diimina run

atoms
Ni   0.022615419  0.037783871  0.025751533 f=k
N    0.386170317  1.871072585  0.306265538 f=k
C    1.612863056  2.248007643  0.148716016 f=k
C    2.540686607  1.163409862 -0.183603690 f=k
N    1.976290003  0.008161589 -0.301176178 f=k
H   -0.288333328  2.609667211  0.546869047 f=k
H    1.942601454  3.283060847  0.269249237 f=k
H    3.613259273  1.338293482 -0.302134814 f=k
H    2.621707427 -0.766258151 -0.517479818 f=k
H   -1.351756655  0.253389698  0.386197419 f=k
C   -0.430177075 -1.815433265  0.860288229 f=m
C   -0.363705637 -1.910722338 -0.515633302 f=m
H    0.533109934 -2.284970854 -1.016904201 f=m
H   -1.279922499 -1.884673940 -1.115144723 f=m
H   -1.389295819 -1.753589602  1.377541080 f=m
H    0.440296224 -2.041861443  1.484489314 f=m
end
charge 1
fragments
m t21.etfrag
k t21.Nifrag
end
symmetry NOSYM
xc
 gga scf becke perdew
end
ETSNOCV
print etslowdin
endinput
eor

Next one could do 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
NOCV
  THRESH 0.01
END
END INPUT
eor
mv TAPE41 nocv2.t41

$ADFBIN/densf << eor
GRID MEDIUM
NOCV
  ALL
END
END INPUT
eor
mv TAPE41 nocv3.t41