Use Gaussian、 Spartan or WebMO to calculate the Electron Affinity of atoms with atomic number Hydrogen and Helium, by using B3LYP、MP2 and M062X theoretical methods with 6-31G**、6-311G**、6-31++G** and 6-311++G** basis set, and do some simple statistical analysis.
X(g)+e-→X(g)-
(unit:hartrees)
| neutral atom | multiplicity | B3LYP/6-31G** | B3LYP/6-311G** | B3LYP/6-31++G** | B3LYP/6-311++G** | MP2/6-31G** | MP2/6-311G** | MP2/6-31++G** | MP2/6-311++G** | M062X/6-31G** | M062X/6-311G** | M062X/6-31++G** | M062X/6-311++G** |
| H | 2 | -0.50027 | -0.50216 | -0.50167 | -0.50226 | -0.49823 | -0.49981 | -0.49880 | -0.49982 | -0.49823 | -0.49813 | -0.49830 | -0.49819 |
| He | 1 | -2.90705 | -2.91303 | -2.90908 | -2.91354 | -2.88064 | -2.88458 | -2.88128 | -2.88470 | -2.88064 | -2.90177 | -2.90076 | -2.90203 |
(unit:hartrees)
| anion | multiplicity | B3LYP/6-31G** | B3LYP/6-311G** | B3LYP/6-31++G** | B3LYP/6-311++G** | MP2/6-31G** | MP2/6-311G** | MP2/6-31++G** | MP2/6-311++G** | M062X/6-31G** | M062X/6-311G** | M062X/6-31++G** | M062X/6-311++G** |
| H | 1 | -0.46182 | -0.50986 | -0.53432 | -0.53416 | -0.43539 | -0.48291 | -0.50363 | -0.50561 | -0.40161 | -0.49793 | -0.51967 | -0.51943 |
| He | 2 | -1.49532 | -2.12713 | -2.72206 | -2.74466 | -1.50911 | -2.06436 | -2.67739 | -2.69895 | -1.57984 | -2.13252 | -2.71835 | -2.73573 |
(unit:kcal/mol)
| Electron Affinity | Exp | B3LYP/6-31G** | B3LYP/6-311G** | B3LYP/6-31++G** | B3LYP/6-311++G** | MP2/6-31G** | MP2/6-311G** | MP2/6-31++G** | MP2/6-311++G** | M062X/6-31G** | M062X/6-311G** | M062X/6-31++G** | M062X/6-311++G** |
| H | -17.4 | 24.1 | -4.8 | -20.5 | -20.0 | 39.4 | 10.6 | -3.0 | -3.6 | 60.6 | 0.1 | -13.4 | -13.3 |
| He | 11.5 | 885.9 | 493.1 | 117.4 | 106.0 | 860.6 | 514.7 | 127.9 | 116.6 | 816.3 | 482.7 | 114.5 | 104.4 |
(unit:kcal/mol)
| absolute error | B3LYP/6-31G** | B3LYP/6-311G** | B3LYP/6-31++G** | B3LYP/6-311++G** | MP2/6-31G** | MP2/6-311G** | MP2/6-31++G** | MP2/6-311++G** | M062X/6-31G** | M062X/6-311G** | M062X/6-31++G** | M062X/6-311++G** |
| H | 41.5 | 12.6 | 3.1 | 2.6 | 56.8 | 28.0 | 14.4 | 13.8 | 78.0 | 17.5 | 4.0 | 4.1 |
| He | 874.3 | 481.6 | 105.8 | 94.4 | 849.1 | 503.2 | 116.4 | 105.0 | 804.7 | 471.2 | 102.9 | 92.8 |
(unit:kcal/mol)
(unit:kcal/mol)
結論 :
1. 計算He的電子親和力誤差比H的大
2. 加入diffuse functions之後，計算值明顯更靠近實驗值
3.使用更大的基底函數計算值也會更靠近實驗值
Use Gaussian、 Spartan or WebMO to calculate the Electron Affinity of atoms with atomic number 3~18, by using B3LYP、MP2 and M062X theoretical methods with 6-31G**、6-311G**、6-31+G** and 6-311+G** basis set, and do some simple statistical analysis.
(unit:kcal/mol)
| Electron Affinity | Exp | B3LYP/6-31G** | B3LYP/6-311G** | B3LYP/6-31+G** | B3LYP/6-311+G** | MP2/6-31G** | MP2/6-311G** | MP2/6-31+G** | MP2/6-311+G** | M062X/6-31G** | M062X/6-311G** | M062X/6-31+G** | M062X/6-311+G** |
| Li | -14.3 | -3.7 | -9.8 | -12.6 | -12.9 | 4.4 | -3.6 | -5.7 | -6.6 | -2.2 | -8.8 | -11.4 | -12.0 |
| Be | 11.5 | 34.3 | 17.0 | 5.3 | 5.2 | 45.3 | 25.7 | 15.3 | 14.2 | 40.6 | 23.0 | 10.6 | 10.5 |
| B | -6.5 | 25.0 | 6.4 | 7.6 | -9.3 | 33.2 | 13.3 | 1.2 | -0.4 | 28.8 | 9.2 | -4.2 | -5.1 |
| C | -29.1 | 1.3 | -12.7 | -31.4 | -31.4 | 5.4 | -8.6 | -22.7 | -24.3 | 1.0 | -13.5 | -27.5 | -28.8 |
| N | 1.6 | 35.0 | 27.5 | -3.2 | -3.1 | 54.2 | 48.7 | 20.1 | 20.5 | 39.9 | 32.8 | 5.8 | 5.8 |
| O | -33.7 | 5.0 | -3.6 | -37.4 | -37.1 | 14.0 | 9.7 | -25.1 | -23.1 | 5.3 | -2.5 | -30.1 | -30.1 |
| F | -78.4 | -24.2 | -42.4 | -81.0 | -80.4 | -24.7 | -37.1 | -78.5 | -74.7 | -25.7 | -42.5 | -73.5 | -73.2 |
| Ne | 27.7 | 1009.1 | 813.3 | 157.6 | 151.8 | 1067.9 | 865.9 | 172.0 | 168.8 | 1011.1 | 818.9 | 162.9 | 155.2 |
| Na | -12.6 | -10.3 | -10.3 | -13.7 | -13.5 | -1.4 | -2.7 | -5.9 | -6.1 | -9.3 | -9.9 | -13.0 | -13.1 |
| Mg | 9.2 | 17.4 | 13.8 | 5.4 | 5.2 | 23.1 | 19.2 | 11.2 | 10.9 | 22.8 | 18.5 | 9.6 | 9.5 |
| Al | -10.0 | -0.8 | -5.4 | -8.3 | -8.9 | 5.0 | 1.1 | -1.5 | -2.2 | 2.0 | -2.9 | -5.6 | -5.8 |
| Si | -32.0 | -21.8 | -25.6 | -30.7 | -30.6 | -17.6 | -20.2 | -24.7 | -24.7 | -20.9 | -24.7 | -28.5 | -28.7 |
| P | -17.2 | -6.6 | -20.0 | -20.9 | -21.0 | 14.5 | 1.9 | 0.9 | 0.8 | -5.6 | -18.1 | -18.3 | -18.6 |
| S | -47.9 | -38.1 | -50.2 | -50.6 | -50.6 | -22.1 | -33.0 | -33.3 | -33.3 | -38.1 | -48.7 | -48.6 | -48.6 |
| Cl | -83.3 | -72.8 | -84.4 | -85.6 | -85.9 | -62.5 | -72.2 | -73.5 | -73.7 | -74.1 | -84.4 | -84.6 | -85.0 |
| Ar | 23.1 | 331.8 | 273.9 | 60.7 | 68.0 | 354.7 | 305.8 | 71.0 | 79.3 | 330.5 | 271.6 | 61.0 | 69.7 |
(unit:kcal/mol)
(unit:kcal/mol)
(unit:kcal/mol)
| absolute error | B3LYP/6-31G** | B3LYP/6-311G** | B3LYP/6-31+G** | B3LYP/6-311+G** | MP2/6-31G** | MP2/6-311G** | MP2/6-31+G** | MP2/6-311+G** | M062X/6-31G** | M062X/6-311G** | M062X/6-31+G** | M062X/6-311+G** |
| Li | 10.6 | 4.5 | 1.6 | 1.4 | 18.6 | 10.7 | 8.5 | 7.7 | 12.1 | 5.4 | 2.8 | 2.3 |
| Be | 22.8 | 5.4 | 6.2 | 6.3 | 33.8 | 14.2 | 3.7 | 2.7 | 29.0 | 11.5 | 0.9 | 1.0 |
| B | 31.4 | 12.9 | 14.1 | 2.9 | 39.7 | 19.7 | 7.7 | 6.1 | 35.2 | 15.6 | 2.3 | 1.4 |
| C | 30.4 | 16.4 | 2.3 | 2.3 | 34.5 | 20.5 | 6.4 | 4.8 | 30.1 | 15.6 | 1.6 | 0.3 |
| N | 33.4 | 25.8 | 4.8 | 4.7 | 52.6 | 47.1 | 18.5 | 18.9 | 38.3 | 31.2 | 4.2 | 4.2 |
| O | 38.6 | 30.1 | 3.7 | 3.4 | 47.7 | 43.4 | 8.6 | 10.6 | 39.0 | 31.2 | 3.6 | 3.5 |
| F | 54.2 | 36.1 | 2.6 | 2.0 | 53.7 | 41.4 | 0.0 | 3.7 | 52.8 | 35.9 | 5.0 | 5.2 |
| Ne | 981.4 | 785.6 | 129.9 | 124.1 | 1040.2 | 838.3 | 144.3 | 141.2 | 983.4 | 791.2 | 135.2 | 127.6 |
| Na | 2.4 | 2.3 | 1.1 | 0.8 | 11.2 | 9.9 | 6.8 | 6.5 | 3.3 | 2.8 | 0.4 | 0.4 |
| Mg | 8.1 | 4.6 | 3.9 | 4.1 | 13.8 | 10.0 | 2.0 | 1.7 | 13.6 | 9.3 | 0.4 | 0.3 |
| Al | 9.2 | 4.6 | 1.7 | 1.1 | 15.0 | 11.1 | 8.5 | 7.8 | 12.0 | 7.1 | 4.3 | 4.1 |
| Si | 10.2 | 6.5 | 1.4 | 1.4 | 14.5 | 11.8 | 7.4 | 7.3 | 11.2 | 7.4 | 3.5 | 3.3 |
| P | 10.6 | 2.8 | 3.7 | 3.8 | 31.7 | 19.1 | 18.2 | 18.0 | 11.7 | 0.9 | 1.1 | 1.4 |
| S | 9.8 | 2.3 | 2.7 | 2.7 | 25.8 | 14.9 | 14.6 | 14.6 | 9.8 | 0.8 | 0.7 | 0.7 |
| Cl | 10.5 | 1.1 | 2.3 | 2.6 | 20.8 | 11.1 | 9.9 | 9.6 | 9.2 | 1.1 | 1.3 | 1.7 |
| Ar | 308.7 | 250.9 | 37.6 | 45.0 | 331.6 | 282.8 | 47.9 | 56.2 | 307.4 | 248.6 | 37.9 | 46.7 |
| Mean absolute error | 98.3 | 74.5 | 13.7 | 13.0 | 111.6 | 87.9 | 19.6 | 19.8 | 99.9 | 76.0 | 12.8 | 12.8 |
(unit:kcal/mol)
(unit:kcal/mol)
結論 :
1. 計算電子親和力時，鈍氣的誤差很大
2. 加入diffuse functions之後，計算值明顯更靠近實驗值
3.使用更大的基底函數計算值也會更靠近實驗值
reference : https://en.wikipedia.org/wiki/Electron_affinity_(data_page)