J J CYCLOHEXANE J J

HF Calcula0ons for Cyclohexane Done by Jill

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Energy in

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Reac1on Pathway for Cyclohexane

0.00 Kcal/mol

12.346 Kcal/mol

6.763 Kcal/mol

7.822 Kcal/mol

All Calcula0ons, Provided by Desiree

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Energy in

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Reac1on Pathway for Cyclohexane

Color Method

Red B3LYP

Blue HF

Green MP2

HF 0 Kcal/mol B3LYP 0 Kcal/mol MP2 0 Kcal/mol

HF 12.35 Kcal/mol B3LYP 11.49 Kcal/mol MP2 12.84 Kcal/mol

HF 6.76 Kcal/mol B3LYP 6.53 Kcal/mol MP2 6.61 Kcal/mol

HF 7.82 Kcal/mol B3LYP 7.34 Kcal/mol MP2 8.12 Kcal/mol

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Energy in

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Version 2.0

Misc. Informa0on

Chair Conforma1on Symmetry: D3d Nature of Cri0cal Point: Minimum Job Number 408148 Imaginary Freq: None

Half Chair Conforma1on Symmetry: Cs Nature of Cri0cal Point: TS Job Number 408518/408524 Imaginary Freq: 2

1. A -241.8873 cm-1 2. A -46.0441 cm-1

Twist Boat Conforma1on Symmetry: D2 Nature of Cri0cal Point: Minimum Job Number 385405 Imaginary Freq: None

Boat Conforma1on Symmetry: C2v Nature of Cri0cal Point: TS Job Number 408151 Imaginary Freq: 1

1. A2 -104.4427 cm-1

Ques0ons and Such 1. A Poten0al Energy Surface is a map of a molecules energy as a func0on of that molecules degrees of freedom. This takes the energy of a group of nuclei and their electrons against the geometric coordinates. This can include bond length as well as bond angle. 2. The cri0cal points on a PES are called sta0onary points. They are classied as local minima or saddle points. On a PES, a cri0cal point has a rst deriva0ve of the poten0al energy for each geometric parameter, of zero. 3. You locate sta0onary points where nding points on the PES where the rst deriva0ve is zero in all direc0ons. This is done via a computer algorithm. 4. You determine the nature of the sta0onary points by using the second deriva0ve test. For a transi0on state the second deriva0ve is greater than zero except along the reac0on coordinate where it is less than zero. For a minimum, the second deriva0ve is greater than zero. 5. No, this energy does not match that provided by HF calcula0ons. This is because HF and MP2 have dierent zero point energies. For MP2 (which Glen used) there was a zero point energy of 0.175106 Hartree but for HF (which I had) there was a zero point energy of 0.182246 Hartree.