Incorrect args for pair coefficients/Pair coeff for hybrid has invalid style

Whoops, sorry, will fix that up. The message is posted again below:

Dear Axel,

Thank you for your reply! But I want to clarify something. If I can only use the pair_coeff * * syntax, does it have to be pair_coeff * *….or can it be pair_coeff 1 1….(where 1 is the atom type.) If it can only be pair_coeff * *…., how can assign the appropriate potentials to the appropriate atom types?

Thank you and appreciate your help!

Bes Regards,
Amelia

The pair hybrid doc page explains all of these issues.

Some pair styles can use pair_coeff 1 1, some cannot.

Steve

Whoops, sorry, will fix that up. The message is posted again below:

Dear Axel,

Thank you for your reply! But I want to clarify something. If I can only use the pair_coeff * * syntax, does it have to be pair_coeff * *….or can it be pair_coeff 1 1….(where 1 is the atom type.) If it can only be pair_coeff * *…., how can assign the appropriate potentials to the appropriate atom types?

You are asking the wrong question. Even if you could use the pair_coeff syntax with numbers, your simulation would be bogus. The potentials you chose are not pairwise additive and mixing and matching as you want to do us extremely inconsistent. Ideally you want all atom types parameterized in the same style and for a reasonably similar setup. When doing a hybrid with manybody potentials, you want each set of manybody parameters operate on a mostly isolated part of the system and then use a pairwise additive potential to connect the subsystems.

Axel

Dear all,

Thank you so much for your help! I managed to fix the problem, which was really a trivial mistake in syntax. As for the ‘pairwise additive problem’, I switched out tersoff potential for Lennard-Jones as that is also suitable for the interaction between Graphene and Iron:

pair_coeff * * airebo CH.airebo C NULL
pair_coeff * * eam/fs Fe_p1.eam.fs NULL Fe
pair_coeff 1 2 lj/cut 1.0 1.0

Once again, thank you!

Best Regards,
Amelia

Dear all,

Thank you so much for your help! I managed to fix the problem, which was
really a trivial mistake in syntax. As for the ‘pairwise additive problem’,
I switched out tersoff potential for Lennard-Jones as that is also suitable
for the interaction between Graphene and Iron:

pair_coeff * * airebo CH.airebo C NULL
pair_coeff * * eam/fs Fe_p1.eam.fs NULL Fe
pair_coeff 1 2 lj/cut 1.0 1.0

your LJ parameters are bogus!

Dear Axel,

The specified LJ parameters were just random values I inputed to see if the pair_coeff format worked. I have to do more research on the actual parameters for the LJ potential to get a more accurate simulation.

Best Regards,
Amelia