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Re: [lammps-users] Kokkos Reax Package Development Plan
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Re: [lammps-users] Kokkos Reax Package Development Plan


From: "James Kress" <jimkress_58@...5633...>
Date: Tue, 27 Jun 2017 14:37:09 -0400

Stan,

 

Thank for your response.  Improving the performance of qeq is a worthy goal. 

 

Unfortunately, the qeq method (and EEM) has a few drawbacks, the worst being its inability to restrain long-range charge-transfer, even between molecular fragments that are well separated, or by unphysically reducing the charge on species like OH-, Na+, etc. in a biomolecular environment.

 

ACKS2 significantly reduces these problems and is why the current ReaxFF method incorporates it as the charge equilibration methodology.  Some descriptive overview can be found here:

https://www.nature.com/articles/npjcompumats201511

 

And the references cited therein go into more detail.

 

An independent, coded implementation of ACKS2 can be found here:

https://github.com/tovrstra/validation_eem_acks2_reaxff

 

I would suggest it to you for your inspection to see if it might facilitate ACKS2 implementation in the Kokkos package.

 

Thanks for your consideration.

 

Jim

 

From: Moore, Stan [mailto:stamoor@...3...]
Sent: Tuesday, June 27, 2017 1:16 PM
To: jimkress_58@...5633...; lammps-users@lists.sourceforge.net
Cc: Thompson, Aidan <athomps@...3...>
Subject: RE: Kokkos Reax Package Development Plan

 

Jim,

 

We are currently working on implementing the Extended-Lagrangian scheme for fix qeq in LAMMPS USER-REAXC, see the discussion here: https://github.com/lammps/lammps/issues/507. Once this is in the regular version of LAMMPS it could easily be added to the Kokkos version as well. Aidan, anything to add?

 

Stan

 

From: James Kress [mailto:jimkress_58@...5813....]
Sent: Monday, June 26, 2017 4:03 PM
To: lammps-users@...13...ge.net
Cc: Moore, Stan <stamoor@...3...>
Subject: [EXTERNAL] Kokkos Reax Package Development Plan

 

Is there any working being done on (or planned for) the Kokkos Reax package to incorporate ACKS2 and eReaxFF?

 

 

Jim Kress