I need to simulate the interaction (physisorption) between H2 molecule and CNTs. I model C-C/C-H/H-H interactions with AIREBO potential.
The problem resides when I try to keep close the H atoms to form the H2 molecule. I know that this force cannot be well modeled with a classical force. I overcame
that problem by using the “rigid” command for each pair of H atom.
Is that method good ?
Any suggestions is highly appreciate.
Thank in advance
If you just have many pairs of H atoms to make rigid as H2 molecules,
then I would use fix shake and not fix rigid. The former will be
more efficient for that purpose. You will need to define a bond
potential that defines the bond length you want.
Dear Steve,
Thanks for your answer. The H atoms are close to form a H2 molecules… but, sometimes, as soon as they approach the CNT walls, the H2 molecules simply disappear. I tried to make smaller the timestep but it does not work.
Does anyone have any ideas?? Thanks a lot again.
Giuseppe
Why do they disappear? Where do they go? Are they blown
out of the box? You need to figure this out, maybe by doing
viz of your system. I doubt this is a problem with a rigid vs
non-rigid model.
Dear Romano,
Since AIREBO is a dynamic potential, is it possible that the bonds might start broken during the coarse of the simulation and the individual atoms just fly away?