[gmx-users] Parameters for bonded interactions

[Mark Abraham]

On 15/08/2012 9:46 AM, Sebastien Cote wrote:
> Dear Gromacs users,
>
> In the topology file of the protein, we see every two atoms that share a bond, three atoms that share a bond angle, and four atoms that share a torsion angle. However, the parameters (equilibrium value, energy constant, phase) are not explicitly shown as Gromacs fetch them in the ffbonded table. My question: Is there a simple way to see (without having to look at the code) which parameters are associated to which bond length, bond angle and torsion angle?
>
> More specifically, I would like to know which torsion angle parameters is specifically associated to each torsion angle. In the ffbonded table, there is sometimes different groups of four atoms that can be associated to the same torsion angle as there is the 'X' atom which can be any atom.

grompp -pp writes out a post-processed topology, which may be what you need.

Otherwise you can inspect the contents of the .tpr file to see which 
interaction gets which parameters. That is not easy for a large system, 
but is definitive.

Mark