林奕諄-第九週作業
1.Please use ChatGPT to explore a thematic series of questions within the scope of computational chemistry and follow up with further inquiries about any unfamiliar terms ( except homework )
2.Find the transition state and calculate the barrier height (ΔV≠) for the following reaction.
reaction：HNC → HCN
methods : MP2/aug-cc-pVTZ、MP2/6-31+G**
program : gaussian 16
Structures & IRC
Method:MP2/aug-cc-pVTZ
reactant structure transition state structure prouduct structure
With calculation of IRC, it can make sure my optimized structures of transition state correct.
figure :IRC ( Method:MP2/aug-cc-pVTZ )
Method:MP2/6-31+G**
reactant structure transition state structure prouduct structure
With calculation of IRC, it can make sure my optimized structures of transition state correct.
figure :IRC ( Method:MP2/6-31+G** )
barrier height (ΔV≠)
ΔV≠=(ETS-EHNC)(hartress/particles)*627.5095=ΔV≠(Kcal/mol)
| ΔV≠ | HNC (Hartree/Particle) | TS (Hartree/Particle) |
ΔV≠ (Kcal/mol) |
| MP2/6-31+G** | 93.14306 | 93.08701 | 35.2 |
| MP2/aug-cc-pVTZ | 93.23130 | 93.17648 | 34.4 |
3.Calculate the k(rate constant) in different temperatures (at least 3 different temperatures) for the following reaction and plot of ln(k) versus 1000/T then compare with the experimental values.
reaction：CH4 +OH․→ H2O + CH3․
| T(K) | k(EXP) | k(MP2/aug-cc-pVTZ) | k(MP2/6-31+G**) | |
| 298 | 8.50E-15 | 1.20E-14 | 7.90E-15 | |
| 500 | 1.50E-13 | 5.40E-13 | 2.20E-13 | |
| 700 | 4.80E-13 | 2.00E-12 | 7.60E-13 | |
| T(K) | 1000/T | lnk(EXP) | lnk(MP2/aug-cc-pVTZ) | lnk(MP2/6-31+G**) | |
| 298 | 3.4 | -32.4 | -32.08 | -32.48 | |
| 500 | 2 | -29.5 | -28.25 | -29.14 | |
| 700 | 1.4 | -28.37 | -26.95 | -27.91 |
reaction：CD4 +OH․→ H2O(1 H will replace by D) + CD3․
| T(K) | k(MP2/aug-cc-pVTZ) | k(MP2/6-31+G**) |
| 298 | 1.60E-15 | 9.90E-16 |
| 500 | 1.10E-13 | 6.30E-14 |
| 700 | 8.20E-13 | 4.50E-13 |
| T(K) | 1000/T | lnk(MP2/aug-cc-pVTZ) | lnk(MP2/6-31+G**) |
| 298 | 3.4 | -34.07 | -34.55 |
| 500 | 2 | -29.82 | -30.39 |
| 700 | 1.4 | -27.83 | -28.43 |
methods : MP2/aug-cc-pVTZ、MP2/6-31+G**
| KIE | (MP2/aug-cc-pVTZ) | (MP2/6-31+G**) |
| 298 | 7.32 | 7.98 |
| 500 | 4.82 | 3.51 |
| 700 | 2.4 | 1.68 |