Regarding Potential issue

Hi,

In my system I have 4 types of atoms.

  1. Copper
    2.Copper
    3.Hydrogen
  2. Tungsten.
    I was using these potentials for my simulation.

pair_style hybrid/overlay bop lj/cut 2.5 eam/alloy
pair_coeff * * bop CuH.bop.table Cu Cu H NULL
comm_modify cutoff 11.4
pair_coeff 1*2 4 lj/cut 0.00174466548 3.437227
pair_coeff * * potential-WHHe-EAM1.eam.alloy NULL NULL H W

But it says Pair coeff for hybrid has invalid style. Thanks for your time.

Best,
Joy

Hi,

In my system I have 4 types of atoms.
1. Copper
2.Copper
3.Hydrogen
4. Tungsten.
I was using these potentials for my simulation.
pair_style hybrid/overlay bop lj/cut 2.5 eam/alloy
pair_coeff * * bop CuH.bop.table Cu Cu H NULL
comm_modify cutoff 11.4
pair_coeff 1*2 4 lj/cut 0.00174466548 3.437227
pair_coeff * * potential-WHHe-EAM1.eam.alloy NULL NULL H W
But it says Pair coeff for hybrid has invalid style. Thanks for your time.

...and rightfully so, since your last pair_coeff line is not
compatible with a hybrid pair style.

there is another serious problem with this section of the input. you
are computing interactions for hydrogen twice. that is not correct.
besides, this kind of input should work with a plain hybrid pair
style, not hybrid/overlay.

axel.

Dear Dr. Axel,

Thanks for your reply. Why the last line is not compatible with hybrid pair style? As far as I have read from the doc file, I can use the NULL keyword to omit the interactions while using eam/alloy with hybrid pair style.

I know that I am computing the H-H interactions twice with bop and eam/alloy. Can I use lj/cut instead like this?

pair_style hybrid bop lj/cut 2.5 lj/cut 2.5 meam
pair_coeff * * bop CuH.bop.table Cu Cu H NULL
comm_modify cutoff 11.4
pair_coeff 1*2 4 lj/cut 1 0.00174466548 3.437227
pair_coeff 3 4 lj/cut 2 0.00449760054 3.205241313
pair_coeff * * meam W.library.meam W W.meam NULL NULL NULL W

Thanks for the time again!

Dear Dr. Axel,

Thanks for your reply. Why the last line is not compatible with hybrid pair style?

please compare it to the documentation.

As far as I have read from the doc file, I can use the NULL keyword to omit the interactions while using eam/alloy with hybrid pair style.

I know that I am computing the H-H interactions twice with bop and eam/alloy. Can I use lj/cut instead like this?
pair_style hybrid bop lj/cut 2.5 lj/cut 2.5 meam
pair_coeff * * bop CuH.bop.table Cu Cu H NULL
comm_modify cutoff 11.4
pair_coeff 1*2 4 lj/cut 1 0.00174466548 3.437227
pair_coeff 3 4 lj/cut 2 0.00449760054 3.205241313
pair_coeff * * meam W.library.meam W W.meam NULL NULL NULL W

that depends on what kind of a structure you have and what the
distribution of the hydrogen and metal atoms is.
you can only use a hybrid pair style with multiple manybody potentials
and expect meaningful results, if there is a good separation between
those sections.
if this an alloy-like compound with all the different atom types
mixed, then you need one manybody potential style and parameter set
for *everything*.

BTW: there is no need for specifying lj/cut twice and the cutoff for
lj/cut seems bogus.

axel.

didn't we have the same discussion before already?