Table 1. Errors in the Estimated QM/MM Polarization Energy for a Methanol Molecule Solvated in a Cubic Box of 1000 Water Moleculesa.
| 6-31+G*
basis |
6-311++G**
basis |
||||||||
|---|---|---|---|---|---|---|---|---|---|
| functional | scheme | MSE | RMS | MAX | REL | MSE | RMS | MAX | REL |
| B3LYP | MESS-E | –0.386 | 0.432 | 1.339 | 20.6% | –0.420 | 0.470 | 1.459 | 21.2% |
| MESS-H(15) | 0.066 | 0.071 | 0.173 | 4.0% | 0.101 | 0.107 | 0.234 | 5.7% | |
| MESS-H(30) | –0.016 | 0.033 | 0.176 | 1.0% | 0.019 | 0.032 | 0.112 | 1.5% | |
| MESS-H(60) | –0.029 | 0.044 | 0.216 | 1.4% | –0.030 | 0.048 | 0.241 | 1.5% | |
| M06-2X | MESS-E | –0.047 | 0.084 | 0.358 | 3.3% | –0.078 | 0.113 | 0.462 | 4.3% |
| MESS-H(15) | 0.090 | 0.097 | 0.230 | 5.2% | 0.140 | 0.150 | 0.356 | 7.7% | |
| MESS-H(30) | –0.014 | 0.032 | 0.170 | 1.0% | 0.028 | 0.039 | 0.118 | 1.9% | |
| MESS-H(60) | –0.025 | 0.041 | 0.205 | 1.3% | –0.026 | 0.043 | 0.218 | 1.3% | |
| ωB97X-D | MESS-E | 0.048 | 0.071 | 0.209 | 3.8% | 0.048 | 0.075 | 0.223 | 3.7% |
| MESS-H(15) | 0.067 | 0.072 | 0.173 | 4.0% | 0.095 | 0.103 | 0.247 | 5.4% | |
| MESS-H(30) | –0.010 | 0.030 | 0.151 | 1.0% | 0.014 | 0.031 | 0.122 | 1.4% | |
| MESS-H(60) | –0.027 | 0.042 | 0.208 | 1.3% | –0.028 | 0.046 | 0.229 | 1.4% | |
a
Mean signed errors (MSE), root mean square errors (RMS), maximum errors (MAX), all in kcal/mol, in the QM/MM polarization energies estimated with MESS-E and MESS-H schemes are listed, together with the average of the relative unsigned error (REL). For the MESS-H calculations, the number within the parentheses refers to the number of eigenvectors used in the construction of the inverse of the electronic Hessian. Averaged over 1000 configurations from a 1 ns trajectory.