I have been playing with a polymer called glyme, and I have run Tinker analyze on it to get OPLS-AA parameters for it. I have attached the output parameter file to this post.

My question is, how do I go from the parameters given in the Tinker parameter file (ff.out) under "Improper Torsion Parameters" and "Torsional Angle Parameters" and translate those into a GROMACS topology file (UNL_4E9C7F.itp)? Both of these files are for benzene. Getting the bond and angle constants was a simple unit change but how does it work for the IMPROPER DIHEDRAL ANGLES?

The Improper Torsion Parameters according to the Tinker file are:

Amplitude = 1.667, Phase = 180.0, Periodicity = 2

Under IMPROPER DIHEDRAL ANGLES, I see that

Phase = 180.0, Phase = 180.0, Periodicity = 2

However, how do I make the change?

Similarly, for IMPROPER DIHEDRAL ANGLES, is there a way to convert the Torsional Angle Parameters?

I would appreciate any advice you have for me!

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