How to implement Stillinger-Weber (SW) Three-Body Interaction in GROMACS?

User discussions
1

GROMACS version:2024.4
GROMACS modification: Yes/No
Dear GROMACS users,

I am trying to implement the Stillinger-Weber (SW) three-body interaction potential in GROMACS for my simulation. The potential is given by:

V_SW(r1,r2,θ)=ϵ(cos⁡θ−cos⁡θ_0)^2 exp⁡(σ/r1−σ) exp⁡(σ/r2−σ)

r1 and r2 are the distances between the central atom (A2) and its two neighbors (A1 and A3)
θ is the bond angle between A1-A2-A3
ε is the energy scaling factor, σ is the characteristic length, and θ_0 is the equilibrium angle for the system

Could someone tell me how to use this potential in the GROMACS force field? Specifically, I would like to know how to parameterize it within GROMACS

2

Hi,

Stillinger-Weber is not supported by Gromacs, as any other 3-body non-bonded potentials. As far as I understand, it’s quite computationally and memory expensive and doesn’t really offer any modeling advantage for biophysics simulations.

Other codes like LAMMPS support this kind of potentials, but they are (inevitably) slower.

BTW why do you need Stillinger-Weber?