Table 3. Multicomponent DFT Proton Affinity Errors Relative to the Experimental Values, Mean Absolute Errors (MAE), and Maximum Absolute Errors (MaxAE) for Different Electronic Basis Setsa.
| molecule | experiment | aug-cc-pVnZ |
aug-cc-pVnZ-mc |
||||
|---|---|---|---|---|---|---|---|
| DZ | TZ | QZ | DZ | TZ | QZ | ||
| CN– | 15.31 | –0.24 | –0.20 | –0.18 | –0.19 | –0.15 | –0.15 |
| NO2– | 14.75 | –0.14 | –0.09 | –0.07 | –0.08 | –0.04 | –0.04 |
| NH3 | 8.85 | 0.01 | 0.02 | 0.03 | 0.05 | 0.06 | 0.06 |
| HCOO– | 14.97 | –0.13 | –0.10 | –0.08 | –0.07 | –0.05 | –0.05 |
| HO– | 16.95 | –0.14 | –0.11 | –0.09 | –0.08 | –0.07 | –0.07 |
| HS– | 15.31 | –0.23 | –0.19 | –0.17 | –0.18 | –0.14 | –0.14 |
| H2O | 7.16 | 0.01 | 0.04 | 0.06 | 0.06 | 0.08 | 0.09 |
| H2S | 7.31 | –0.03 | –0.04 | –0.06 | 0.07 | –0.08 | –0.09 |
| CO | 6.16 | –0.05 | –0.01 | 0.01 | 0.00 | 0.03 | 0.03 |
| N2 | 5.12 | –0.01 | 0.03 | 0.06 | 0.04 | 0.07 | 0.08 |
| CO2 | 5.60 | –0.01 | 0.03 | 0.05 | 0.05 | 0.07 | 0.07 |
| CH2O | 7.39 | –0.01 | –0.04 | –0.02 | 0.02 | 0.01 | 0.01 |
| MAE | 0.08 | 0.07 | 0.07 | 0.08 | 0.07 | 0.07 | |
| MaxAE | 0.24 | 0.20 | 0.18 | 0.19 | 0.15 | 0.15 | |
a
A negative proton affinity error indicates the multicomponent DFT proton affinity is smaller than the experimental value. All values are reported in eV.