A GROMOS-Compatible Force Field for Small Organic Molecules in the Condensed Phase: The 2016H66 Parameter Set.

This article reports on the calibration and validation of a new GROMOS-compatible parameter set 2016H66 for small organic molecules in the condensed phase. The calibration is based on 62 organic molecules spanning the chemical functions alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine, amide, thiol, sulfide, and disulfide, as well as aromatic compounds and nucleic-acid bases. For 57 organic compounds, the calibration targets are the experimental pure-liquid density ρliq and the vaporization enthalpy ΔHvap, as well as the hydration free energy ΔGwat and the solvation free energy ΔGche in cyclohexane, at atmospheric pressure and at (or close to) room temperature. The final root-mean-square deviations (RMSD) for these four quantities over the set of compounds are 32.4 kg m–3, 3.5 kJ mol–1, 4.1 kJ mol–1, and 2.1 kJ mol–1, respectively, and the corresponding average deviations (AVED) are 1.0 kg m–3, 0.2 kJ mol–1, 2.6 kJ mol–1, and 1.0 kJ mol–1, respectively. For the five nucleic-acid bases, the ...