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[[VBTutorial4| return to Tutorial n°4]]
 
[[VBTutorial4| return to Tutorial n°4]]
 
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Two geometries are provided the planar and the twisted where a vinyl part C1 C5 has been twisted by 90°.
==planar.inp==
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this second moieties has its pi orbitals along the y direction.
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==Evaluation of the conjugaison==
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{| class="collapsible collapsed wikitable"
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|-
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!'''Planar geometry'''
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|-
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|
 
<html><pre>
 
<html><pre>
 
  $contrl maxit=200 scftyp=rhf runtyp=ENERGY DFTTYP=B3LYP ICHARG=0 $end
 
  $contrl maxit=200 scftyp=rhf runtyp=ENERGY DFTTYP=B3LYP ICHARG=0 $end
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  H    1.0  0.0000000000  0.3149214640  -2.3230051413
 
  H    1.0  0.0000000000  0.3149214640  -2.3230051413
 
  $END
 
  $END
</pre></html>
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</pre></html>  
 +
 
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Corresponding files are planar.inp and planar-deconj.inp
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|}
 
Localization of px-like pi orbitals to deconjugate keeping planar
 
Localization of px-like pi orbitals to deconjugate keeping planar
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{| class="collapsible collapsed wikitable"
 +
|-
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!'''BLW part'''
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|-
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|
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px-like pi orbitals on C1=C2 and on C3=C4
 
<html><pre>
 
<html><pre>
 
  $BLW NBLOCK=3 ITER=50  $END
 
  $BLW NBLOCK=3 ITER=50  $END
Ligne 33 : Ligne 48 :
 
  $END
 
  $END
 
</pre></html>
 
</pre></html>
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|}
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==Evaluation of the hyperconjugaison in the twisted form==
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{| class="collapsible collapsed wikitable"
 +
|-
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!'''Twisted (perpendicular) geometry'''
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|-
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|
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<html><pre>
 +
$contrl maxit=200 scftyp=rhf runtyp=ENERGY DFTTYP=B3LYP ICHARG=0 $end
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$SYSTEM TIMLIM=600000 MEMORY=100000000 $END
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$BASIS  GBASIS=N31 NGAUSS=6 NDFUNC=1 $END
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$DATA
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  BLW-ED Analysis
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  C1 
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C    6.0  0.000000  -1.086858    2.236154
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C    6.0  0.000000    0.000000    1.489418
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C    6.0  0.000000    0.000000    0.000000
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C    6.0  -1.086858    0.000000  -0.746736
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H    1.0  0.967527    0.000000  -0.478451
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H    1.0  0.000000    0.967527    1.967869
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H    1.0  -2.072275    0.000000  -0.314213
 +
H    1.0  -1.029400    0.000000  -1.820913
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H    1.0  0.000000  -2.072275    1.803631
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H    1.0  0.000000  -1.029400    3.310331
 +
$END
 +
 +
</pre></html>
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|}
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In the BLW part we localize px-like pi orbitals of atoms C1=C2 and  py-like orbitals for C3=C4 to avoid hyperconjugaison.
 +
{| class="collapsible collapsed wikitable"
 +
|-
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!'''BLW-Localized part'''
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|-
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|<html><pre>
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$BLW NBLOCK=3 ITER=50  $END
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 +
$BLWDAT
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  2 8 0
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  3  7 13 14 18 22 28 29
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  2 8 0
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34 38 43 45 49 53 58 60
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  26 56 -1
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$END
 +
 +
</pre></html>
 +
Corresponding files are twisted.inp and twisted-blw.inp
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|}
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 +
:We find
 +
:planar delocalized  -155.8824504889
 +
:planar localized  -155.8603462862  (13.9 kcal/mol)
 +
:Perpendicular        -155.8695790387    ( 8.1 kcal/mol)
 +
:Perpendicular but localized -155.8537320442  (18.0 kcal/mol)
 +
Hence conjugaison is 13.9 kcal/mol, and the hyper conjugaison in the twisted form is as large as 9.9 kcal/mol

Dernière version du 11 juillet 2012 à 17:33

return to Tutorial n°4 Two geometries are provided the planar and the twisted where a vinyl part C1 C5 has been twisted by 90°. this second moieties has its pi orbitals along the y direction.

Evaluation of the conjugaison

Localization of px-like pi orbitals to deconjugate keeping planar

Evaluation of the hyperconjugaison in the twisted form

In the BLW part we localize px-like pi orbitals of atoms C1=C2 and py-like orbitals for C3=C4 to avoid hyperconjugaison.

We find
planar delocalized -155.8824504889
planar localized -155.8603462862 (13.9 kcal/mol)
Perpendicular -155.8695790387 ( 8.1 kcal/mol)
Perpendicular but localized -155.8537320442 (18.0 kcal/mol)

Hence conjugaison is 13.9 kcal/mol, and the hyper conjugaison in the twisted form is as large as 9.9 kcal/mol