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Update fix ACKS2 docs

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Stan Gerald Moore
2022-04-01 12:45:38 -06:00
parent 2f895d63a6
commit ea9e3c0860
1 changed files with 37 additions and 16 deletions
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53
doc/src/fix_acks2_reaxff.rst
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@ -19,6 +19,12 @@ Syntax
* cutlo,cuthi = lo and hi cutoff for Taper radius
* tolerance = precision to which charges will be equilibrated
* params = reaxff or a filename
* one or more keywords or keyword/value pairs may be appended
.. parsed-literal::
keyword = *maxiter*
*maxiter* N = limit the number of iterations to *N*
Examples
""""""""
@ -26,7 +32,7 @@ Examples
.. code-block:: LAMMPS
fix 1 all acks2/reaxff 1 0.0 10.0 1.0e-6 reaxff
fix 1 all acks2/reaxff 1 0.0 10.0 1.0e-6 param.acks2
fix 1 all acks2/reaxff 1 0.0 10.0 1.0e-6 param.acks2 maxiter 500
Description
"""""""""""
@ -44,14 +50,14 @@ the charge equilibration performed by fix acks2/reaxff, see the
The ACKS2 method minimizes the electrostatic energy of the system by
adjusting the partial charge on individual atoms based on interactions
with their neighbors. It requires some parameters for each atom type.
with their neighbors. It requires some parameters for each atom type.
If the *params* setting above is the word "reaxff", then these are
extracted from the :doc:`pair_style reaxff <pair_reaxff>` command and
the ReaxFF force field file it reads in. If a file name is specified
for *params*\ , then the parameters are taken from the specified file
and the file must contain one line for each atom type. The latter form
must be used when performing QeQ with a non-ReaxFF potential. The lines
should be formatted as follows:
for *params*, then the parameters are taken from the specified file
and the file must contain one line for each atom type. The latter
form must be used when performing QeQ with a non-ReaxFF potential.
The lines should be formatted as follows:
.. parsed-literal::
@ -67,13 +73,25 @@ ReaxFF potential file, except that eta is defined here as twice the eta
value in the ReaxFF file. Note that unlike the rest of LAMMPS, the units
of this fix are hard-coded to be A, eV, and electronic charge.
**Restart, fix_modify, output, run start/stop, minimize info:**
The optional *maxiter* keyword allows changing the max number
of iterations in the linear solver. The default value is 200.
.. note::
In order to solve the self-consistent equations for electronegativity
equalization, LAMMPS imposes the additional constraint that all the
charges in the fix group must add up to zero. The initial charge
assignments should also satisfy this constraint. LAMMPS will print a
warning if that is not the case.
Restart, fix_modify, output, run start/stop, minimize info
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
No information about this fix is written to :doc:`binary restart files
<restart>`. No global scalar or vector or per-atom quantities are
stored by this fix for access by various :doc:`output commands
<Howto_output>`. No parameter of this fix can be used with the
*start/stop* keywords of the :doc:`run <run>` command.
<restart>`. This fix computes a global scalar (the number of
iterations) for access by various :doc:`output commands <Howto_output>`.
No parameter of this fix can be used with the *start/stop* keywords of
the :doc:`run <run>` command.
This fix is invoked during :doc:`energy minimization <minimize>`.
@ -86,12 +104,12 @@ This fix is invoked during :doc:`energy minimization <minimize>`.
Restrictions
""""""""""""
This fix is part of the REAXFF package. It is only enabled if LAMMPS
was built with that package. See the :doc:`Build package
<Build_package>` doc page for more info.
This fix is part of the REAXFF package. It is only enabled if
LAMMPS was built with that package. See the :doc:`Build package
<Build_package>` page for more info.
This fix does not correctly handle interactions involving multiple
periodic images of the same atom. Hence, it should not be used for
periodic images of the same atom. Hence, it should not be used for
periodic cell dimensions less than 10 angstroms.
This fix may be used in combination with :doc:`fix efield <fix_efield>`
@ -105,7 +123,10 @@ Related commands
:doc:`pair_style reaxff <pair_reaxff>`, :doc:`fix qeq/reaxff <fix_qeq_reaxff>`
**Default:** none
Default
"""""""
maxiter 200
----------