Lesson 1 -- simple TST calculation

Objective: Calculate thermal rate constants of the hydrogen abstraction by hydroxyl radical at ethane, C2H6? + OH = C2H5? + HOH, using the simple TST method with no tunneling correction.

Prerequisite: For TST calculations, geometries, energies, and frequencies of the reactants and the transition state are needed. So prior to rate calculations, the users should use a quantum chemistry package to optimize the geometries of these stationaries points and perform frequency calculations at the optimized geometries. This will help to determine if the transition state found is actually the correct one for the given reaction.

• C2H6_BHHLYP_ccpvdz.log: Reactant - ethane C2H6? .

• OH_BHHLYP_ccpvdz.log: Reactant - hydroxyl radical OH.

• TS_C2H6-OH_BHHLYP_ccpvdz.log: Transition State.

Procedure: In the TheRate GUI, enter the following information in the appropriate place:

1. Task Description: "Rate constant calculation for rxn C2H6? + OH = C2H5? + H2O? using TST method with not tunneling correction"
2. Method: "TST"
3. Reaction sym. number: Forward "6"
4. Choose either T-range or T-list. In this example, T-range is chosen --> Enter: Low: 300 | High: 3000 | Interval: 100
5. Tunneling: "None"
6. Print: either "Normal" OR "Long". In this example, "Normal" option is chosen.
7. In the Reactant tab:
   1. Click on "Add" button --> A pop-up window named "Add Kinatics" appears --> Click on "File" --> Choose "Open" --> Choose the file C2H6? _BHHLYp_ccpvdz.log --> Click on "Save".
   2. Repeat the same steps but for OH_BHHLYP_ccpvdz.log.
8. In the Transition State tab: do the same step as in step 7 but for TS
9. Save the file as: C2H6-OH_TST.kinetics.inp: Kinetics input file
10. Click on "Submit" button in order to have the input run.
11. Save the output as: C2H6-OH_TST.kinetics.out: Kinetics output file
    
12. View the output OR plot the results

• C2H6_BHHLYP_ccpvdz.FChk: Fchk file for ethane
  
• OH.Fchk: Fchk file for OH
• TS_C2H6-OH_BHHLYP_ccpvdz.Fchk: Fchk file for TS