[gmx-users] Adding 3 body potential

[Mehmet Suezen]

Hello,

I`d like to add 3-body potential into Gromacs source:
a,b,c,d,e are free parameters, t is angle between 1st,2nd and 3rd
particle. r12 and r13 are 
distances between particles.

      f(r12,r13,a,b,c,d,e,t) =
e*a*exp(b*(1/(r12/c-d)+1/(r13/c-d)))*(cos(t)-1/3)**2

Which routine should I modify in order to build in such functional form.

Thanks for any help.

Mehmet