Zero Interaction Energy

LAMMPS LAMMPS Beginners
1

Dear All,

I have two water drops on a carbon substrate. To compute the interaction energy between one of the drops and surface substrate, I did as follows:

  group    water type 1 2 
  group    left_drop id 1 52413
  group    right_drop id 52414 104826
  group    carbon type 3

  compute cInt left_drop group/group carbon 
  fix fInt all ave/time 100 10 1000 c_cInt file E_h2o_C.data

Strangely, I get zero interaction energy. However, when I changed the above commands to :

compute cInt water group/group carbon

the interaction energy will be nonzero. Hereby it seems something wrong with interaction energy computations for one of the drops and carbon surface.

Thanks for your suggestions and comments …

2

Not enough information here. Why does the left_drop group only have 2 atoms? How do you know they are close enough to interact?

1 Like
3

Or maybe you actually meant a range of ids instead, like 1 to 52413, which needs a colon ??

 group    left_drop id 1:52413

See group command — LAMMPS documentation

1 Like
4

Yes, it needs a colon. Thanks for your useful reply.