Accuracy Test of the OPLS-AA Force Field for Calculating Free Energies of Mixing and Comparison with PAC-MAC
| Autor: | Johannes G. E. M. Fraaije, Augustinus J. M. Sweere |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Activity coefficient
010304 chemical physics Mean squared error OPLS Chemistry Analytical chemistry Thermodynamics Thermodynamic integration Binary number 010402 general chemistry 01 natural sciences Force field (chemistry) Article 0104 chemical sciences Computer Science Applications Molecular dynamics 0103 physical sciences Vaporization Physical and Theoretical Chemistry |
| Zdroj: | Journal of Chemical Theory and Computation |
| ISSN: | 1549-9626 |
| Popis: | We have calculated the excess free energy of mixing of 1053 binary mixtures with the OPLS-AA force field using two different methods: thermodynamic integration (TI) of molecular dynamics simulations and the Pair Configuration to Molecular Activity Coefficient (PAC-MAC) method. PAC-MAC is a force field based quasi-chemical method for predicting miscibility properties of various binary mixtures. The TI calculations yield a root mean squared error (RMSE) compared to experimental data of 0.132 kBT (0.37 kJ/mol). PAC-MAC shows a RMSE of 0.151 kBT with a calculation speed being potentially 1.0 × 104 times greater than TI. OPLS-AA force field parameters are optimized using PAC-MAC based on vapor–liquid equilibrium data, instead of enthalpies of vaporization or densities. The RMSE of PAC-MAC is reduced to 0.099 kBT by optimizing 50 force field parameters. The resulting OPLS-PM force field has a comparable accuracy as the OPLS-AA force field in the calculation of mixing free energies using TI. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|