[lammps-users] Contents of lammps-users Digest, Vol 56, Issue 92, topic 5

Message: 5
Date: Sun, 23 Jan 2011 17:32:57 -0500
From: Axel Kohlmeyer <[email protected]…43…4…>
Subject: Re: [lammps-users] Non-reactive MD with ReaxFF
To: Farshad Saberi Movahed <[email protected]…1969…>
Cc: “[email protected]
<[email protected]>
Message-ID:
<AANLkTi=[email protected]…25…>
Content-Type: text/plain; charset=ISO-8859-1

do you have any confirmation for
that from some published literature?

cheers,
axel.

Hi, Axel,

In Chenoweth, van Duin, and Goddard’s J. Phys. Chem. A 2008, 112, 1040-1053 paper, it was mentioned on page 1042 that “During the equilibration simulations, the C-O and H-O bond parameters were switched off to prevent reactions from occurring during the equilibration of the system. The equilibrated systems were then used in NVT-MD simulations where the temperature was set to 2500 K using a temperature damping constant of 0.5 ps and a MD time step of 0.1 fs.”

Can I do something similar with LAMMPS/ReaxFF or LAMMPS/ReaxFF-c?

Thanks a lot!

Regards,

Xiao

1 Like

Message: 5
Date: Sun, 23 Jan 2011 17:32:57 -0500
From: Axel Kohlmeyer <[email protected]>
Subject: Re: [lammps-users] Non-reactive MD with ReaxFF
To: Farshad Saberi Movahed <[email protected]>
Cc: "[email protected]"
<[email protected]>
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=ISO-8859-1

do you have any confirmation for
that from some published literature?

cheers,
axel.

Hi, Axel,

In Chenoweth, van Duin, and Goddard's J. Phys. Chem. A 2008, 112, 1040-1053
paper, it was mentioned on page 1042 that "During the equilibration
simulations, the C-O and H-O bond parameters were switched off to prevent
reactions from occurring during the equilibration of the system. The
equilibrated systems were then used in NVT-MD simulations where the
temperature was set to 2500 K using a temperature damping constant of 0.5 ps
and a MD time step of 0.1 fs."

Can I do something similar with LAMMPS/ReaxFF or LAMMPS/ReaxFF-c?

you can certainly modify the parameter files according to those
instructions. this doesn't require any modification of LAMMPS itself.

cheers,
    axel.

Aidan might have a suggestion on how to do this in the param file
(input to LAMMPS).

Steve

There is no way to do this in "user mode." You would either have to modify
the code (more hard) or modify the ffield.reax file (less hard). Either way,
you will have to understand the structure of the ReaxFF potential to get the
desired behavior.