The bond-dissociation energy (BDE) workflow computes the energy of homolytically breaking a bond (i.e. where the electrons in a bond are split equally between both fragments). It first optimizes the starting molecule according to the desired mode and computing the energy of the starting molecule. It then iterates over all bonds to be broken and generates the fragments. Each fragment is optimized and a single point energy is taken. The BDE is then the difference in energy between the fragments and the intact molecule, with a correction factor to account for missing zero-point, enthalpy, and relativistic effects.
| Mode | Optimization | Single Point |
|---|---|---|
| Rapid NNP | OMol25's eSEN Conserving Small | OMol25's eSEN Conserving Small |
| Rapid Semiempirical | GFN2-xTB | g-xTB |
| Careful DFT | GFN2-xTB | r²SCAN-3c |
The following corrections are applied, and are taken from the paper ExpBDE54: A Slim Experimental Benchmark for Exploring the Pareto Frontier of Bond-Dissociation-Enthalpy-Prediction Methods.
| Mode | Slope | Intercept | RMSE |
|---|---|---|---|
| Rapid NNP | 0.916 | 2.206 | 3.557 |
| Rapid Semiempirical | 0.928 | −0.295 | 4.658 |
| Careful DFT | 0.945 | 3.303 | 4.013 |
"Rapid NNP" is recommended for most work.