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(Undo revision 5649 by Benoit (Talk))
(Undo revision 5648 by Benoit (Talk))
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<big>'''2.1 Computations'''</big>
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<big>'''Computations'''</big>
  
 
Compute the Energies and Wavefunctions at Reactant and Transition State with Different Sets of VB Structures
 
Compute the Energies and Wavefunctions at Reactant and Transition State with Different Sets of VB Structures
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<big>'''2.2 Analysis: Wavefunctions and Energies'''</big>
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<big>'''Analysis: Wavefunctions and Energies'''</big>
 
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# Compute the Barrier height of the <math>\textrm{S}_{\textrm{N}}2</math> reaction at VBSCF and VBCISD levels. See the difference of the barrier heights.
 
# Compute the Barrier height of the <math>\textrm{S}_{\textrm{N}}2</math> reaction at VBSCF and VBCISD levels. See the difference of the barrier heights.
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<big>'''2.3 Optional : Compute all points and draw the VBSCDs at VBSCF and VBCISD levels.'''</big>
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<big>'''Optional : Compute all points and draw the VBSCDs at VBSCF and VBCISD levels.'''</big>
 
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| class="collapsible collapsed wikitable"
 
|-
 
!<big>'''BLW within GAMESS (Version: MAR-25-2010 R2)'''</big>
 
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|
 
a- VB Structures used in the computations
 
<center>[[File:Structures.png|600px]] </center><br>
 
<center>Total 8 Structures of The System</center>
 
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<center>[[File:Reactant_Structures.png|400px]] </center><br>
 
<center>Structures of The Reactant State</center>
 
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<center>[[File:Product_Structures.png|400px]] </center><br>
 
<center>Structures of The Product State</center>
 
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b- Computational results
 
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<center>
 
{| border="1"
 
|+ Weights of VB Structures of H-H-H Abstract Reaction at Reactant Geometry
 
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! scope="col" |
 
! scope="col" | S1
 
! scope="col" | S2
 
! scope="col" | S3
 
! scope="col" | S4
 
! scope="col" | S5
 
! scope="col" | S6
 
! scope="col" | S7
 
! scope="col" | S8
 
|-
 
! scope="row" | VBSCF
 
| 0.803 || 0.003 || 0.096 || 0.001 || 0.095 || 0.000 || 0.000 || 0.000
 
|-
 
! scope="row" | VBCISD
 
| 0.770 || 0.005 || 0.110 || 0.003 || 0.111 || 0.000 || 0.000 || 0.001
 
|-
 
|}
 
</center>
 
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<center>
 
{| border="1"
 
|+ Weights of VB Structures of H-H-H Abstract Reaction at Transition State Geometry
 
|-
 
! scope="col" |
 
! scope="col" | S1
 
! scope="col" | S2
 
! scope="col" | S3
 
! scope="col" | S4
 
! scope="col" | S5
 
! scope="col" | S6
 
! scope="col" | S7
 
! scope="col" | S8
 
|-
 
! scope="row" | VBSCF
 
| 0.344 || 0.344 || 0.096 || 0.035 || 0.025 || 0.025 || 0.096 || 0.035
 
|-
 
! scope="row" | VBCISD
 
| 0.358 || 0.358 || 0.059 || 0.036 || 0.046 || 0.046 || 0.059 || 0.036
 
|-
 
|}
 
</center>
 
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<center>
 
{| border="1"
 
|+ Energies (a.u.) and Barriers (kcal/mol) of H-H-H Abstract Reaction
 
! scope="col" |
 
! scope="col" | VBSCF
 
! scope="col" | VBCISD
 
|-
 
! scope="row"      |Reactant 
 
| -1.64637 || -1.66241
 
|-
 
! scope="row"    | Transition State
 
| -1.60706 || -1.63827
 
|-
 
! scope="row"      | Barrier
 
| 24.7 || 15.1
 
|-
 
|}
 
</center>
 
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<center>
 
{| border="1"
 
|+ Energies(a.u.) and Resonance Energies (''B'', in kcal/mol) of H-H-H Abstract Reaction at Reactant Geometry
 
! scope="col" |
 
! scope="col" | VBSCF
 
! scope="col" | VBCISD
 
|-
 
! scope="row"      | All Structures 
 
| -1.64637 || -1.66241
 
|-
 
! scope="row"      | Reactant
 
| -1.64617 || -1.66208
 
|-
 
! scope="row"      | Product
 
| -1.40873 || -1.41851
 
|-
 
! scope="row"      | ''B''
 
| 0.1 || 0.2
 
|-
 
|}
 
</center>
 
<br>
 
<center>
 
{| border="1"
 
|+ Energies (a.u.) and Resonance Energies (''B'', in kcal/mol) of H-H-H Abstract Reaction at Transition State Geometry
 
! scope="col" |
 
! scope="col" | VBSCF
 
! scope="col" | VBCISD
 
|-
 
|-
 
! scope="row"    | All Structures
 
| -1.60706 || -1.63827
 
|-
 
! scope="row"    | Reactant
 
| -1.54798 || -1.56655
 
|-
 
! scope="row"    | Product
 
| -1.54798 || -1.56655
 
|-
 
! scope="row"      | ''B''
 
| 37.1 || 45.0
 
|-
 
|}
 
</center>
 
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<center><big>Optional : VBSCDs for H-H-H abstract reaction by VBSCF and VBCISD</big></center>
 
  
[[File:H3-VBSCD-VBSCF.png|500px]]  [[File:H3-VBSCD-VBCISD.png|500px]]<br>
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[[Answer Exercise2 of tutorial 3|>> Answer]]
<big> {{pad|250px}} VBSCF  {{pad|420px}}  VBCISD </big>
 
|}
 
  
 
== Exercise 3 (paper exercise) : Conical intersection in H<sub>3</sub><sup>•</sup> radical ==
 
== Exercise 3 (paper exercise) : Conical intersection in H<sub>3</sub><sup>•</sup> radical ==

Version du 12 juillet 2012 à 12:06

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Valence Bond State correlation diagrams

Exercise 1 : Computation of state correlation Diagrams for a 3 centers / 4 electrons system

In this exercise the <math>\textrm{S}_{\textrm{N}}2</math> reaction Cl<math>{}^{-}</math> + CH3Cl -> ClCH3 + Cl<math>{}^{-}</math> will be studied in both vacuum and solution. Valence Bond State Correlation Diagrams (VBSCD) will be constructed at <math>\pi</math>-D-BOVB level. There are two parts in this exercise: basic part and optional part. The basic part is performed with MCP-DZP basis set in which the inner orbitals in Cl and C are described with MCP pseudo potential. The optional part is performed with 6-31+G* basis set, using the general specification for the xmvb input (expert users). Only reactant and transition state will be computed in this exercise, which is sufficient to build the VBSCD diagrams.

>> general guidelines for BOVB calculations