LAMMPS WWW Site - LAMMPS Documentation - LAMMPS Mailing List Archives
Re: [lammps-users] [EXTERNAL] hi about the potential parameters of latte
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [lammps-users] [EXTERNAL] hi about the potential parameters of latte


From: "Goldman, Nir" <goldman14@...87...>
Date: Thu, 19 Oct 2017 13:52:05 +0000

Hi All,

 

To follow up, regarding DFTB+/LAMMPS, Steve is correct: in this case, DFTB+ is the driver. It calls LAMMPS as a library, which then “calls back” to DFTB+ each time step to pass in coordinates and lattice vectors and then receive the system forces and components of the stress tensor. I had to make some modifications to the DFTB+ code, which I would be happy to share with any interested parties.

 

Regarding a comparison of DFTB+ and LATTE, both are very similar in spirit as both are derived from a density functional tight binding formalism. I’ve never used LATTE, so I can’t comment on it, specifically. However, I would caution any potential user to thoroughly test either code to assess its accuracy and computational efficiency for a given system of interest. Density functional tight binding is a semi-empirical formalism, so there’s no guarantee that an off the shelf parameterization will yield usable results.   

 

Hope that helps,

 

Nir

 

--

Nir Goldman

Material Sciences Division, PLS

Lawrence Livermore National Laboratory

P.O. Box 808, L-282

Livermore, CA 94551-0808

Phone: (925) 422-3994

https://pls.llnl.gov/people/staff-bios/msd/goldman-n

 

From: Steve Plimpton <sjplimp@...24...>
Date: Wednesday, October 18, 2017 at 9:14 AM
To: Oleg Sergeev <seoman@...567...>
Cc: Steve Plimpton <sjplimp@...3...>, "Song, Zhigong" <zhigong_song@...802...>, "cawkwell@...795..." <cawkwell@...795...>, "cnegre@...795..." <cnegre@...795...>, "lammps-users@lists.sourceforge.net" <lammps-users@lists.sourceforge.net>, "Goldman, Nir" <goldman14@...87...>
Subject: Re: [lammps-users] [EXTERNAL] hi about the potential parameters of latte

 

I'll leave comparisons of LATTE and DFTB+ to the experts.

I'm CCing Nir Goldman (LLNL) who has coupled DFTB+ and LAMMPS

for modeling he has done.  I believe what he did was add

some code to DFTB+ to call LAMMPS as a library.  I'm not clear on

if that version of DFTB+ is publicly available - Nir can comment.

From a software point of view the coupling of LAMMPS to the 2

codes is the inverse of each other, though both accomplish the

same thing,

For LATTE, LAMMPS is the driver, if calls LATTE as a lib each timestep,

thru fix latte as a wrapper.  It passes coords, and receives back forces.

For DFTB+, it is the driver, it calls LAMMPS as a library, and the

LAMMPS script that is run includes a fix external command, which does a callback

to DFTB+ each timestep to pass coords and receive back forces.

Nir added a new Fortran interface to the LAMMPS lib to facilitate

this - see examples/COUPLE/fortran_dftb.

Steve

 

 

On Mon, Oct 16, 2017 at 11:44 AM, Oleg Sergeev <seoman@...567...> wrote:

Dear Zhigong,

 

I believe there are also parameter files for MgO. Don't know if those are of interest to you.

 

And I also have another question of, I think, general interest to other users. As far as I know, while the LATTE interface is new, LAMMPS can be and in the past was already used with DFTB+ code for running TB simulations. From the user point of view, what are the main advantages of one code over the other?

 

Regards,

Oleg

 

16.10.2017, 20:00, "Steve Plimpton" <sjplimp@...3...>:

Hi - Marc and Christian are the right folks to answer this,
as it's really a LATTE Q. I'm also CCing this to
the LAMMPS mail list, as I think the Q/A will be of
general interest to other LAMMPS users who want
to try out tight-binding and LATTE.

Marc/Christian - if you CC the mail list address
in your replies, the info should appear there as well.

Thanks,
Steve

 

 From: "Song, Zhigong" <zhigong_song@...802...>
 Date: Sat, 14 Oct 2017 15:19:05 -0400
 Cc: cnegre@...795..., sjplimp@...3...
 Content-Type: multipart/alternative; boundary="001a113b0cc89a18ad055b86a52b"

 [1:text/plain Hide]
 This is a heavy lammps users from Brown University. I am very excited to
 find that tight-binding method is implemented with lammps and make it
 complie successfully. However, when I finished the testing in example
 directory, I realized that there are only C,H,N,O potentials within. I am
 forced on mechanical properties of materials Thus, I am just wondering if
 there are TB potentials of other elements. Or where could I get them?
 Thanks a lot for all your contributions on it,


 Best
 [2:text/html Show]


------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
lammps-users mailing list
lammps-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/lammps-users


------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
lammps-users mailing list
lammps-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/lammps-users