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pair_lj_sf.txt
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.. index:: pair_style lj/sf
pair_style lj/sf command
========================
pair_style lj/sf/omp command
============================
Syntax
""""""
.. parsed-literal::
pair_style lj/sf cutoff
* cutoff = global cutoff for Lennard-Jones interactions (distance units)
Examples
""""""""
.. parsed-literal::
pair_style lj/sf 2.5
pair_coeff * * 1.0 1.0
pair_coeff 1 1 1.0 1.0 3.0
Description
"""""""""""
Style *lj/sf* computes a truncated and force-shifted LJ interaction
(Shifted Force Lennard-Jones), so that both the potential and the
force go continuously to zero at the cutoff :ref:`(Toxvaerd) <Toxvaerd>`:
.. image:: Eqs/pair_lj_sf.jpg
:align: center
The following coefficients must be defined for each pair of atoms
types via the :doc:`pair_coeff <pair_coeff>` command as in the examples
above, or in the data file or restart files read by the
:doc:`read_data <read_data>` or :doc:`read_restart <read_restart>`
commands, or by mixing as described below:
* epsilon (energy units)
* sigma (distance units)
* cutoff (distance units)
The last coefficient is optional. If not specified, the global
LJ cutoff specified in the pair_style command is used.
----------
Styles with a *gpu*\ , *intel*\ , *kk*\ , *omp*\ , or *opt* suffix are
functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
hardware, as discussed in :doc:`Section_accelerate <Section_accelerate>`
of the manual. The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.
These accelerated styles are part of the GPU, USER-INTEL, KOKKOS,
USER-OMP and OPT packages, respectively. They are only enabled if
LAMMPS was built with those packages. See the :ref:`Making LAMMPS <start_3>` section for more info.
You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the :ref:`-suffix command-line switch <start_7>` when you invoke LAMMPS, or you can
use the :doc:`suffix <suffix>` command in your input script.
See :doc:`Section_accelerate <Section_accelerate>` of the manual for
more instructions on how to use the accelerated styles effectively.
----------
**Mixing, shift, table, tail correction, restart, rRESPA info**\ :
For atom type pairs I,J and I != J, the epsilon and sigma
coefficients and cutoff distance for this pair style can be mixed.
Rin is a cutoff value and is mixed like the cutoff. The
default mix value is *geometric*\ . See the "pair_modify" command for
details.
The :doc:`pair_modify <pair_modify>` shift option is not relevant for
this pair style, since the pair interaction goes to 0.0 at the cutoff.
The :doc:`pair_modify <pair_modify>` table option is not relevant
for this pair style.
This pair style does not support the :doc:`pair_modify <pair_modify>`
tail option for adding long-range tail corrections to energy and
pressure, since the energy of the pair interaction is smoothed to 0.0
at the cutoff.
This pair style writes its information to :doc:`binary restart files <restart>`, so pair_style and pair_coeff commands do not need
to be specified in an input script that reads a restart file.
This pair style can only be used via the *pair* keyword of the
:doc:`run_style respa <run_style>` command. It does not support the
*inner*\ , *middle*\ , *outer* keywords.
----------
Restrictions
""""""""""""
This pair style is part of the USER-MISC package. It is only enabled
if LAMMPS was built with that package. See the :ref:`Making LAMMPS <start_3>` section for more info.
Related commands
""""""""""""""""
:doc:`pair_coeff <pair_coeff>`
**Default:** none
----------
.. _Toxvaerd:
**(Toxvaerd)** Toxvaerd, Dyre, J Chem Phys, 134, 081102 (2011).
.. _lws: http://lammps.sandia.gov
.. _ld: Manual.html
.. _lc: Section_commands.html#comm
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