林昶廷-第7週作業 1031
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.Calculate the structures and atomization energies (AE) of XHn (X = H~Ne) by using B3LYP、MP2 theoretical methods with 6-31+G(d,p)、aug-cc-pVTZ then compare with the experimental values.
- Atomization energies 6-31+G(d,p) Unit:(Kcal/mol)
| AHn | B3LYP | MP2 | Expt |
| H2 | 106.0 | 101.2 | 104.2 |
| LiH | 56.9 | 45.2 | 56.6 |
| BeH2 | 150.7 | 141.0 | 151.6 |
| BH3 | 281.6 | 269.5 | 270.3 |
| CH4 | 422.8 | 399.3 | 397.5 |
| NH3 | 300.2 | 268.0 | 280.3 |
| H2O | 222.0 | 212.5 | 221.6 |
| HF | 131.9 | 130.3 | 136.4 |
- Atomization energies aug-cc-pVTZ Unit:(Kcal/mol)
| AHn | B3LYP | MP2 | Expt |
| H2 | 104.1 | 98.8 | 104.2 |
| LiH | 58.4 | 51.8 | 56.6 |
| BeH2 | 150.7 | 142.0 | 151.6 |
| BH3 | 284.7 | 271.1 | 270.3 |
| CH4 | 421.4 | 411.4 | 397.5 |
| NH3 | 357.8 | 284.4 | 280.3 |
| H2O | 222.8 | 221.9 | 221.6 |
| HF | 132.2 | 136.3 | 136.4 |
- Energy Absolute errors Unit:(Kcal/mol)
| Absolute error | ||||
| HX | B3LYP/6-31+G(d,p) | MP2/6-31+G(d,p) | B3LYP/aug-cc-pVTZ | MP2/aug-cc-pVTZ |
| H2 | 1.83 | 3.04 | 0.10 | 5.41 |
| LiH | 0.26 | 11.41 | 1.79 | 4.83 |
| BeH2 | 0.92 | 10.63 | 0.86 | 9.60 |
| BH3 | 11.31 | 0.84 | 14.44 | 0.81 |
| CH4 | 25.30 | 1.83 | 23.94 | 13.88 |
| NH3 | 19.93 | 12.35 | 77.49 | 4.08 |
| H2O | 0.44 | 9.10 | 1.25 | 0.29 |
| HF | 4.54 | 6.11 | 4.22 | 0.07 |
| MAE | 8.07 | 6.91 | 15.51 | 4.87 |
- Bond length(unit:Å)
| AHn | B3LYP/6-31+G(d,p) | MP2/6-31+G(d,p) | B3LYP/aug-cc-pVTZ | MP2/aug-cc-pVTZ | Expt |
| H2 | 0.743 | 0.734 | 0.742 | 0.737 | 0.741 |
| LiH | 1.614 | 1.623 | 1.59 | 1.605 | 1.595 |
| BeH2 | 1.331 | 1.328 | 1.33 | 1.33 | 1.326 |
| BH3 | 1.193 | 1.185 | 1.188 | 1.187 | 1.19 |
| CH4 | 1.093 | 1.086 | 1.088 | 1.086 | 1.087 |
| NH3 | 1.013 | 1.012 | 1.013 | 1.07 | 1.012 |
| H2O | 0.965 | 0.963 | 0.962 | 0.96 | 0.958 |
| HF | 0.928 | 0.927 | 0.924 | 0.922 | 0.917 |
| MAE | -0.00675 | -0.004 | -1.111375 | -0.008875 |
- Bond angle
| AHn | B3LYP/6-31+G(d,p) | MP2/6-31+G(d,p) | B3LYP/aug-cc-pVTZ | MP2/aug-cc-pVTZ | Expt |
| H2 | - | - | - | - | - |
| LiH | - | - | - | - | - |
| BeH2 | 180 | 180 | 180 | 180 | 180 |
| BH3 | 120 | 120 | 120 | 120 | 120 |
| CH4 | 109.471 | 109.471 | 109.47 | 108.47 | 109.5 |
| NH3 | 107.2 | 108.2 | 107.2 | 109.47 | 106.7 |
| H2O | 105.72 | 105.4 | 105.1 | 104.2 | 104.5 |
| HF | - | - | - | - |
結論:根據平均絕對誤差 ，可以發現MP2/aug-cc-pVTZ計算較準確，是較好的方法