Fig. 1.

Structure of SM16. The colors highlight the origin of force field parameterization for partial charges and torsional interactions. The color of the circle (red or blue) indicates the source of partial charges, and the color of the lines (red or black) connecting the circles indicates the source of torsional parameters. Red stands for parameterization based on [8], blue stands for parameterization based on new calculations reported in this work, and black corresponds to the original OPLS-AA parameters. There is reason to stress that all parameters for bonds and valence angle description are taken from the original OPLS-AA force field. Lennard-Jones parameters originate from OPLS-AA except for long hydrocarbons, which were derived in [8] (see text).