[gmx-users] Adding 3 body potential

[David van der Spoel]

On Wed, 19 Dec 2001, Mehmet Suezen wrote:

>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.
The important thing is: is this a fixed list? i.e. can you define the 
particles 1,2,3 before the simulation?

In that case you can just go into src/gmxlib/bondfree.c and add a new 
angle routine.

Groeten, David.
________________________________________________________________________
Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
Husargatan 3, Box 576,  	75123 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://zorn.bmc.uu.se/~spoel
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++