Influence of the Treatment of Nonbonded Interactions on the Thermodynamic and Transport Properties of Pure Liquids Calculated Using the 2016H66 Force Field.

Abstract

The effect of different treatments of the nonbonded interactions in simulations employing the recently introduced GROMOS-compatible 2016H66 force field is evaluated based on calculations carried out with the GROMACS software. This is done considering four thermodynamic and transport properties (pure liquid density, vaporization enthalpy, surface-tension coefficient, and self-diffusion constant) of 58 organic liquids representative of the chemical groups alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine, amide, thiol, sulfide, disulfide, and aromatic compounds, also including water (SPC model). A dipalmitoylphosphatidylcholine bilayer system is considered as well. The simulated properties are found to be very sensitive to the treatment of the long-range dispersion interactions, notably for the least polar systems. In general, the treatment of the long-range electrostatic or Lennard-Jones interactions using homogeneous correction terms or lattice-sum approaches yield similar results, with punctual discrepancies. The combination of a lattice-sum approach for the electrostatic interactions with a straight-cutoff truncation of the Lennard-Jones interactions at a distance of at least 1.2 nm is found to represent a good compromise setup within GROMACS for achieving compatibility with the reference results obtained using GROMOS as well as a comparable level of agreement with the experimental data. This study also reveals two potential issues with the GROMACS software, related to an incorrect calculation of the pressure when using LINCS in version 4.0.7 and an inadequate implementation of the twin-range scheme in version 5.1.2.