Writing eam_db.tdb in Lammps

OpenKIM
1

Hi Ryan,
As you have mentioned in “Conversion of LAMMPS 2NN MEAM parameters to 2NN MEAM potential parametes for MEAM_2NN__MD_111291751625_000” , we have to create eam_db.tdb file for using it in lammps , but how i am suppose to write it down in lammps ?

pair_style kim KIMvirial MEAM_2NN__MD_111291751625_000
pair_coeff * * eam_db.tdb Si C

is the above way is correct? ,

I want to use Si and C elements

Thanks and Regards,

Digvijay

2

Hello,

You cannot use the Model Driver directly. Instead, you would want to create a Model that uses the model driver by bundling the parameter file with some additional files (makefile, etc.). See the https://openkim.org/dev-kim-item/MEAM_2NN_Fe_to_Ga__MO_145522277939_001 files for an example.

However, it sounds to me like you just want to use the Si and C parameters stored in the eam_db.tdb parameter file associated with the MEAM_2NN_Fe_to_Ga__MO_145522277939_001 model. To do that in lammps you would just do something like this:

pair_style kim KIMvirial MEAM_2NN_Fe_to_Ga__MO_145522277939_001
pair_coeff * * Si C

Cheers,

Ryan

3

Hi,
What is the difference between

MEAM_2NN_Fe_to_Ga__MO_145522277939_001 and MEAM_2NN__MD_111291751625_001 ?

where I should create my “make file” and eam_db.tdb file from above two model drivers for using Si and C interaction with meam potential ?

I have attached one make file is that correct ? because both driver have different way of witting make file which one to follow ?

Thanks and Regards,
Digvijay

Makefile (417 Bytes)

4

Hi Digvijay,

On Tue, May 15, 2018 at 5:48 AM, Digvijay Yadav [email protected] wrote:

Hi,
What is the difference between
MEAM_2NN_Fe_to_Ga__MO_145522277939_001 and MEAM_2NN__MD_111291751625_001 ?

where I should create my “make file” and eam_db.tdb file from above two
model drivers for using Si and C interaction with meam potential ?

As Ryan alluded to above, the difference is
that MEAM_2NN__MD_111291751625_001 is a Model Driver (as indicated by the
‘MD’ in its id), whereas MEAM_2NN_Fe_to_Ga__MO_145522277939_001 is an
actual Model (as indicated by the ‘MO’ in its id); the difference is
briefly noted on https://openkim.org/getting-started/kim-content/. To be
clear, you can think of a Model Driver as consisting of the functional form
of a potential, whereas the specific parameter values are contained in the
Model (although Models do not need to make use of a Model Driver; they can
contain both the functional form and the parameter values).

Although not clear from its name, MEAM_2NN_Fe_to_Ga__MO_145522277939_001
does indeed support Si and C. Therefore, you should simply have to install
this Model Driver and Model (see the “Installing KIM Models” section on
https://openkim.org/kim-api/). If you’re using the
kim-api-v1-collections-management tool, it should automatically compile the
Model Driver and Model for you, so you don’t need to worry about the
Makefiles or anything else. The only other important thing is to make sure
LAMMPS is compiled with support for KIM (see Sec. 4.10 in the LAMMPS
package docs http://lammps.sandia.gov/doc/Section_packages.html). Then
you can use the commands Ryan gives above in your LAMMPS input script.

Perhaps I’m misunderstanding your intent — is there a reason you can’t
just use MEAM_2NN_Fe_to_Ga__MO_145522277939_001 as-is? Are you
specifically trying to Model silicon carbide (which doesn’t appear to be
supported in eam_db.tdb)?

Dan