Hi everyone,

Attached is a script to create Mesocite forcefields using the Boltzmann Inversion method. This method is based on fitting the coarse-grained interactions to spatial distributions, as measured in a fine-grained (i.e. molecular dynamics) trajectory.

The input to the script is a coarse-grained trajectory, which can be obtained from a ordinary molecular dynamics trajectory using the TrajectoryCoarseGrainer script, posted. The output of the script is a forcefield, listing all the bond, angle, and van der Waals interactions relevant to the input structure. The forcefield parameters are fitted, such that there is a reasonable match with the spatial distributions in the input trajectory. All is documented in a PDF file.

An example is provided for OMCTS, a cyclic tetramer of dimethylsiloxane, which is coarse-grained to a ring of 4 beads. The script generates a forcefield for coarse-grained OMCTS, which can be used in Mesocite for further refinement.

Please note the disclaimer: This custom script is compatible with Materials Studio version 6.0. It is provided "as is" and is NOT supported by Accelrys nor is it warranted for any purpose whatsoever. The user assumes responsibility for any malfunctions or bugs.

Hope it is of use to anyone!

Reinier