[gmx-users] Inclusion of an angle-angle cross term?

[Mark Abraham]

Lee-Ping wrote:
> Hi there,
> 
> I'm working on fitting some force field parameters to a batch of ab-initio
> single-point force calculations, and the fit still needs improvement.  I'm
> thinking of including an angle-angle cross term in my custom force field,
> but so far I haven't found that GROMACS can implement this.  I think that
> five atom labels and three parameters are needed to describe such an
> interaction; can GROMACS do this right now?  Thanks.

I don't think so... but check out src/gmxlib/ifunc.c and 
src/gmxlib/bondfree.c for what there is there.

Mark