Computer Modeling of Chemical Systems

1
Computer Modeling of Chemical Systems

• Piti Treesukol

2
Molecular/Ionic Species

• Define initial structure
• Define charge/multiplicity
• Method/Basis set
• Optimized structure
• Obrbitals/Charge density
• Vibrational Frequency
• Energy
• Thermodynamic properties

H2O (0 1) H3O (1 1)
CH3COOH (0 1) CH3COO (1 1)
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Reaction
E(H2O) E(CH3OOH)
E(H2OCH3OOH)
E(H3O) E(CH3OO)
E(H3OCH3OO)
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Energy Profile

• Energy level diagram

5
Common Reactions

• Substitution
• Addition
• Abstraction

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ZSM-5 zeolite

• 3D-crystalline structure

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Straight Channel
8
ZigZagChannel
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(No Transcript)
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ZSM-5
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H-ZSM-5/H2O
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Cluster Model Tailoring
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Cluster Model of H-ZSM-5
Boundary Atoms can be fixed to mimic the crystal
contraints.
Terminatedatoms
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Acidic Zeolite

• Acidity
• OH-Bond length
• Protonation energy
• Effect of framework
• Effect of composition(Si/Al)
• Effect of proton density
• Location of Al ?
• Location of H ?

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Transition State

• H3O H2O

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Basis Set Superposition Error (BSSE)

• E(H3O/small)
• E(H3O/big)