Issues with hybrid potentials

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1

Dear Lammps users,

I am working with hybrid potentials for Argon ,Carbon ,Iron ,carbon (in nanotubes ).

So it consists of 4 types of atoms in the above mentioned order in the read data file.

I used Airebo,LJ and eam potentais to model this.

I have given the pair coefficients commands as shown beolw,

pair_style hybrid airebo 3.0 lj/cut 10.0 eam/fs

pair_coeff * * airebo /home/raji/Desktop/lammps-28Jun14/potentials/CH.airebo NULL C NULL NULL

pair_coeff * * airebo /home/raji/Desktop/lammps-28Jun14/potentials/CH.airebo NULL NULL NULL C

pair_coeff 1 1 lj/cut 0.0103 3.4

pair_coeff 1 2 lj/cut 0.00497 3.4

pair_coeff 1 3 lj/cut 0.516 3.7

pair_coeff 1 4 lj/cut 0.00497 3.4

pair_coeff 2 3 lj/cut 0.02495 3.7

pair_coeff 3 4 lj/cut 0.02495 3.7

pair_coeff * * eam/fs/home/raji/Desktop/lammps-28Jun14/potentials/Fe_mm.eam.fs Fe NULL

But when I ma running the simulation, some errors are coming as

“Pair coeff for hybrid has invalid style (…/pair_hybrid.cpp:351) ”

I am using the latest version of lammps (lammps -28June14)

It would be great if somebody answer to this.

Thanks in advance

Safron

2

Dear Lammps users,

I am working with hybrid potentials for Argon ,Carbon ,Iron ,carbon (in
nanotubes ).

So it consists of 4 types of atoms in the above mentioned order in the read
data file.

I used Airebo,LJ and eam potentais to model this.

I have given the pair coefficients commands as shown beolw,

pair_style hybrid airebo 3.0 lj/cut 10.0 eam/fs

pair_coeff * * airebo /home/raji/Desktop/lammps-28Jun14/potentials/CH.airebo
NULL C NULL NULL

pair_coeff * * airebo /home/raji/Desktop/lammps-28Jun14/potentials/CH.airebo
NULL NULL NULL C

this is not causing the problem you report, but is a different issue.
the second pair_coeff line here will wipe out the first. you need to
specify airebo in the pair style twice and then address those as
"airebo 1" and "airebo 2" in the pair_coeff lines.

pair_coeff 1 1 lj/cut 0.0103 3.4

pair_coeff 1 2 lj/cut 0.00497 3.4

pair_coeff 1 3 lj/cut 0.516 3.7

pair_coeff 1 4 lj/cut 0.00497 3.4

pair_coeff 2 3 lj/cut 0.02495 3.7

pair_coeff 3 4 lj/cut 0.02495 3.7

pair_coeff * *
eam/fs/home/raji/Desktop/lammps-28Jun14/potentials/Fe_mm.eam.fs Fe NULL

But when I ma running the simulation, some errors are coming as

“Pair coeff for hybrid has invalid style (../pair_hybrid.cpp:351) ”

I am using the latest version of lammps (lammps -28June14)

It would be great if somebody answer to this.

hard to say, but easy to find out for you. as is (highly!) recommended
in the manual, run your input with -echo screen so you see the input
as it is being processed line-by-line and you will see on which line
it fails. then you can react. from your input segment, it looks like
you are missing some NULLs for your last pair_coeff line.

axel.

3

> Dear Lammps users,
>
>
> I am working with hybrid potentials for Argon ,Carbon ,Iron ,carbon (in
> nanotubes ).
>
> So it consists of 4 types of atoms in the above mentioned order in the
read
> data file.
>
> I used Airebo,LJ and eam potentais to model this.
>
>
> I have given the pair coefficients commands as shown beolw,
>
> pair_style hybrid airebo 3.0 lj/cut 10.0 eam/fs
>
> pair_coeff * * airebo
/home/raji/Desktop/lammps-28Jun14/potentials/CH.airebo
> NULL C NULL NULL
>
> pair_coeff * * airebo
/home/raji/Desktop/lammps-28Jun14/potentials/CH.airebo
> NULL NULL NULL C

this is not causing the problem you report, but is a different issue.
the second pair_coeff line here will wipe out the first. you need to
specify airebo in the pair style twice and then address those as
"airebo 1" and "airebo 2" in the pair_coeff lines.

> pair_coeff 1 1 lj/cut 0.0103 3.4
>
> pair_coeff 1 2 lj/cut 0.00497 3.4
>
> pair_coeff 1 3 lj/cut 0.516 3.7
>
> pair_coeff 1 4 lj/cut 0.00497 3.4
>
> pair_coeff 2 3 lj/cut 0.02495 3.7
>
> pair_coeff 3 4 lj/cut 0.02495 3.7
>
> pair_coeff * *
> eam/fs/home/raji/Desktop/lammps-28Jun14/potentials/Fe_mm.eam.fs Fe NULL

In addition to a couple of NULLs, you also missed a space between eam/fs
and /home/raji...

Ray

4

Hi,

Thanks for your reply .

I put a space between eam/fs and /home…

Then now the error is coming as "ERROR: Incorrect args for pair coefficients (…/pair_eam_fs.cpp:52) "

I don’t understand what is the wrong with this further ?Please let me know if you have any idea…

Best Regards,

Safron

5

Hi,

Thanks for your reply .
I put a space between eam/fs and /home....

Then now the error is coming as "ERROR: Incorrect args for pair coefficients
(../pair_eam_fs.cpp:52) "

I don’t understand what is the wrong with this further ?Please let me know
if you have any idea..

please revisit the previous mails and read them more carefully.