<span id="index-0"></span><h1>pair_style lj/cut/soft command<a class="headerlink" href="#pair-style-lj-cut-soft-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style lj/cut/coul/cut/soft command<a class="headerlink" href="#pair-style-lj-cut-coul-cut-soft-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style lj/cut/coul/cut/soft/omp command<a class="headerlink" href="#pair-style-lj-cut-coul-cut-soft-omp-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style lj/cut/coul/long/soft command<a class="headerlink" href="#pair-style-lj-cut-coul-long-soft-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style lj/cut/coul/long/soft/omp command<a class="headerlink" href="#pair-style-lj-cut-coul-long-soft-omp-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style lj/cut/tip4p/long/soft command<a class="headerlink" href="#pair-style-lj-cut-tip4p-long-soft-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style lj/cut/tip4p/long/soft/omp command<a class="headerlink" href="#pair-style-lj-cut-tip4p-long-soft-omp-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style lj/charmm/coul/long/soft command<a class="headerlink" href="#pair-style-lj-charmm-coul-long-soft-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style lj/charmm/coul/long/soft/omp command<a class="headerlink" href="#pair-style-lj-charmm-coul-long-soft-omp-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style coul/cut/soft/omp command<a class="headerlink" href="#pair-style-coul-cut-soft-omp-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style coul/long/soft/omp command<a class="headerlink" href="#pair-style-coul-long-soft-omp-command" title="Permalink to this headline">¶</a></h1>
<h1>pair_style tip4p/long/soft/omp command<a class="headerlink" href="#pair-style-tip4p-long-soft-omp-command" title="Permalink to this headline">¶</a></h1>
<div class="section" id="syntax">
<h2>Syntax<a class="headerlink" href="#syntax" title="Permalink to this headline">¶</a></h2>
<li>style = <em>lj/cut/soft</em> or <em>lj/cut/coul/cut/soft</em> or <em>lj/cut/coul/long/soft</em> or <em>lj/cut/tip4p/long/soft</em> or <em>lj/charmm/coul/long/soft</em> or <em>coul/cut/soft</em> or <em>coul/long/soft</em> or <em>tip4p/long/soft</em></li>
<li>args = list of arguments for a particular style</li>
</ul>
<pre class="literal-block">
<em>lj/cut/soft</em> args = n alpha_lj cutoff
n, alpha_LJ = parameters of soft-core potential
cutoff = global cutoff for Lennard-Jones interactions (distance units)
<em>lj/cut/coul/cut/soft</em> args = n alpha_LJ alpha_C cutoff (cutoff2)
n, alpha_LJ, alpha_C = parameters of soft-core potential
cutoff = global cutoff for LJ (and Coulombic if only 1 arg) (distance units)
cutoff2 = global cutoff for Coulombic (optional) (distance units)
<em>lj/cut/coul/long/soft</em> args = n alpha_LJ alpha_C cutoff
n, alpha_LJ, alpha_C = parameters of the soft-core potential
cutoff = global cutoff for LJ (and Coulombic if only 1 arg) (distance units)
cutoff2 = global cutoff for Coulombic (optional) (distance units)
in a free energy calculation in which sites holding electrostatic
charges are being created or anihilated (using
<a class="reference internal" href="fix_adapt_fep.html"><em>fix_adapt/fep</em></a> and <a class="reference internal" href="compute_fep.html"><em>compute_fep</em></a>)
it is important to adapt both the lambda activation parameter (from 0
to 1, or the reverse) and the value of the charge (from 0 to its final
value, or the reverse). This ensures that long-range electrostatic
terms (kspace) are correct. It is not necessary to use core-softed
Coulomb potentials if the van der Waals site is present during the
free-energy route, thus avoiding overlap of the charges. Examples are
provided in the LAMMPS source directory tree, under examples/USER/fep.</p>
<hr class="docutils" />
<p>Styles with a <em>cuda</em>, <em>gpu</em>, <em>intel</em>, <em>kk</em>, <em>omp</em>, or <em>opt</em> 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 <a class="reference internal" href="Section_accelerate.html"><em>Section_accelerate</em></a>
of the manual. The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.</p>
<p>These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
KOKKOS, USER-OMP and OPT packages, respectively. They are only
enabled if LAMMPS was built with those packages. See the <a class="reference internal" href="Section_start.html#start-3"><span>Making LAMMPS</span></a> section for more info.</p>
<p>You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the <a class="reference internal" href="Section_start.html#start-7"><span>-suffix command-line switch</span></a> when you invoke LAMMPS, or you can
use the <a class="reference internal" href="suffix.html"><em>suffix</em></a> command in your input script.</p>
<p>See <a class="reference internal" href="Section_accelerate.html"><em>Section_accelerate</em></a> of the manual for
more instructions on how to use the accelerated styles effectively.</p>
<p>For atom type pairs I,J and I != J, the epsilon and sigma coefficients
and cutoff distance for this pair style can be mixed.
The default mix value is <em>geometric</em>. See the “pair_modify” command
for details.</p>
<p>These pair styles support the <a class="reference internal" href="pair_modify.html"><em>pair_modify</em></a> shift
option for the energy of the Lennard-Jones portion of the pair
interaction.</p>
<p>These pair styles support the <a class="reference internal" href="pair_modify.html"><em>pair_modify</em></a> tail
option for adding a long-range tail correction to the energy and
pressure for the Lennard-Jones portion of the pair interaction.</p>
<p>These pair styles write information to <a class="reference internal" href="restart.html"><em>binary restart files</em></a>, so pair_style and pair_coeff commands do not need
to be specified in an input script that reads a restart file.</p>
</div>
<hr class="docutils" />
<div class="section" id="restrictions">
<h2>Restrictions<a class="headerlink" href="#restrictions" title="Permalink to this headline">¶</a></h2>
<p>To avoid division by zero do not set sigma = 0; use the lambda
parameter instead to activate/deactivate interactions, or use
epsilon = 0 and sigma = 1. Alternatively, when sites do not
interact though the Lennard-Jones term the <em>coul/long/soft</em> or
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