forked from lijiext/lammps
471 lines
24 KiB
HTML
471 lines
24 KiB
HTML
|
|
|
|
<!DOCTYPE html>
|
|
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
|
|
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
|
|
<head>
|
|
<meta charset="utf-8">
|
|
|
|
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
|
|
|
<title>pair_style lj/cut/soft command — LAMMPS 15 May 2015 version documentation</title>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<link rel="stylesheet" href="_static/css/theme.css" type="text/css" />
|
|
|
|
|
|
|
|
<link rel="stylesheet" href="_static/sphinxcontrib-images/LightBox2/lightbox2/css/lightbox.css" type="text/css" />
|
|
|
|
|
|
|
|
<link rel="top" title="LAMMPS 15 May 2015 version documentation" href="index.html"/>
|
|
|
|
|
|
<script src="_static/js/modernizr.min.js"></script>
|
|
|
|
</head>
|
|
|
|
<body class="wy-body-for-nav" role="document">
|
|
|
|
<div class="wy-grid-for-nav">
|
|
|
|
|
|
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
|
|
<div class="wy-side-nav-search">
|
|
|
|
|
|
|
|
<a href="Manual.html" class="icon icon-home"> LAMMPS
|
|
|
|
|
|
|
|
</a>
|
|
|
|
|
|
<div role="search">
|
|
<form id="rtd-search-form" class="wy-form" action="search.html" method="get">
|
|
<input type="text" name="q" placeholder="Search docs" />
|
|
<input type="hidden" name="check_keywords" value="yes" />
|
|
<input type="hidden" name="area" value="default" />
|
|
</form>
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
|
|
|
|
|
|
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_intro.html">1. Introduction</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_start.html">2. Getting Started</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_commands.html">3. Commands</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_packages.html">4. Packages</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_accelerate.html">5. Accelerating LAMMPS performance</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_howto.html">6. How-to discussions</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_example.html">7. Example problems</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_perf.html">8. Performance & scalability</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_tools.html">9. Additional tools</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_modify.html">10. Modifying & extending LAMMPS</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_python.html">11. Python interface to LAMMPS</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_errors.html">12. Errors</a></li>
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_history.html">13. Future and history</a></li>
|
|
</ul>
|
|
|
|
|
|
|
|
</div>
|
|
|
|
</nav>
|
|
|
|
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
|
|
|
|
|
|
<nav class="wy-nav-top" role="navigation" aria-label="top navigation">
|
|
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
|
|
<a href="Manual.html">LAMMPS</a>
|
|
</nav>
|
|
|
|
|
|
|
|
<div class="wy-nav-content">
|
|
<div class="rst-content">
|
|
<div role="navigation" aria-label="breadcrumbs navigation">
|
|
<ul class="wy-breadcrumbs">
|
|
<li><a href="Manual.html">Docs</a> »</li>
|
|
|
|
<li>pair_style lj/cut/soft command</li>
|
|
<li class="wy-breadcrumbs-aside">
|
|
|
|
|
|
<a href="http://lammps.sandia.gov">Website</a>
|
|
<a href="Section_commands.html#comm">Commands</a>
|
|
|
|
</li>
|
|
</ul>
|
|
<hr/>
|
|
|
|
</div>
|
|
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
|
|
<div itemprop="articleBody">
|
|
|
|
<div class="section" id="pair-style-lj-cut-soft-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-lj-cut-soft-omp-command">
|
|
<h1>pair_style lj/cut/soft/omp command<a class="headerlink" href="#pair-style-lj-cut-soft-omp-command" title="Permalink to this headline">¶</a></h1>
|
|
</div>
|
|
<div class="section" id="pair-style-lj-cut-coul-cut-soft-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-lj-cut-coul-cut-soft-omp-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-lj-cut-coul-long-soft-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-lj-cut-coul-long-soft-omp-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-lj-cut-tip4p-long-soft-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-lj-cut-tip4p-long-soft-omp-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-lj-charmm-coul-long-soft-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-lj-charmm-coul-long-soft-omp-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-coul-cut-soft-command">
|
|
<h1>pair_style coul/cut/soft command<a class="headerlink" href="#pair-style-coul-cut-soft-command" title="Permalink to this headline">¶</a></h1>
|
|
</div>
|
|
<div class="section" id="pair-style-coul-cut-soft-omp-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-coul-long-soft-command">
|
|
<h1>pair_style coul/long/soft command<a class="headerlink" href="#pair-style-coul-long-soft-command" title="Permalink to this headline">¶</a></h1>
|
|
</div>
|
|
<div class="section" id="pair-style-coul-long-soft-omp-command">
|
|
<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>
|
|
</div>
|
|
<div class="section" id="pair-style-tip4p-long-soft-command">
|
|
<h1>pair_style tip4p/long/soft command<a class="headerlink" href="#pair-style-tip4p-long-soft-command" title="Permalink to this headline">¶</a></h1>
|
|
</div>
|
|
<div class="section" id="pair-style-tip4p-long-soft-omp-command">
|
|
<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>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style style args
|
|
</pre></div>
|
|
</div>
|
|
<ul class="simple">
|
|
<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)
|
|
<em>lj/cut/tip4p/long/soft</em> args = otype htype btype atype qdist n alpha_LJ alpha_C cutoff (cutoff2)
|
|
otype,htype = atom types for TIP4P O and H
|
|
btype,atype = bond and angle types for TIP4P waters
|
|
qdist = distance from O atom to massless charge (distance units)
|
|
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)
|
|
<em>lj/charmm/coul/long/soft</em> args = n alpha_LJ alpha_C inner outer (cutoff)
|
|
n, alpha_LJ, alpha_C = parameters of the soft-core potential
|
|
inner, outer = global switching cutoffs for LJ (and Coulombic if only 5 args)
|
|
cutoff = global cutoff for Coulombic (optional, outer is Coulombic cutoff if only 5 args)
|
|
<em>coul/cut/soft</em> args = n alpha_C cutoff
|
|
n, alpha_C = parameters of the soft-core potential
|
|
cutoff = global cutoff for Coulomb interactions (distance units)
|
|
<em>coul/long/soft</em> args = n alpha_C cutoff
|
|
n, alpha_C = parameters of the soft-core potential
|
|
cutoff = global cutoff for Coulomb interactions (distance units)
|
|
<em>tip4p/long/soft</em> args = otype htype btype atype qdist n alpha_C cutoff
|
|
otype,htype = atom types for TIP4P O and H
|
|
btype,atype = bond and angle types for TIP4P waters
|
|
qdist = distance from O atom to massless charge (distance units)
|
|
n, alpha_C = parameters of the soft-core potential
|
|
cutoff = global cutoff for Coulomb interactions (distance units)
|
|
</pre>
|
|
</div>
|
|
<div class="section" id="examples">
|
|
<h2>Examples<a class="headerlink" href="#examples" title="Permalink to this headline">¶</a></h2>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style lj/cut/soft 2.0 0.5 9.5
|
|
pair_coeff * * 0.28 3.1 1.0
|
|
pair_coeff 1 1 0.28 3.1 1.0 9.5
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style lj/cut/coul/cut/soft 2.0 0.5 10.0 9.5
|
|
pair_style lj/cut/coul/cut/soft 2.0 0.5 10.0 9.5 9.5
|
|
pair_coeff * * 0.28 3.1 1.0
|
|
pair_coeff 1 1 0.28 3.1 0.5 10.0
|
|
pair_coeff 1 1 0.28 3.1 0.5 10.0 9.5
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style lj/cut/coul/long/soft 2.0 0.5 10.0 9.5
|
|
pair_style lj/cut/coul/long/soft 2.0 0.5 10.0 9.5 9.5
|
|
pair_coeff * * 0.28 3.1 1.0
|
|
pair_coeff 1 1 0.28 3.1 0.0 10.0
|
|
pair_coeff 1 1 0.28 3.1 0.0 10.0 9.5
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style lj/cut/tip4p/long/soft 1 2 7 8 0.15 2.0 0.5 10.0 9.8
|
|
pair_style lj/cut/tip4p/long/soft 1 2 7 8 0.15 2.0 0.5 10.0 9.8 9.5
|
|
pair_coeff * * 0.155 3.1536 1.0
|
|
pair_coeff 1 1 0.155 3.1536 1.0 9.5
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style lj/charmm/coul/long 2.0 0.5 10.0 8.0 10.0
|
|
pair_style lj/charmm/coul/long 2.0 0.5 10.0 8.0 10.0 9.0
|
|
pair_coeff * * 0.28 3.1 1.0
|
|
pair_coeff 1 1 0.28 3.1 1.0 0.14 3.1
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style coul/long/soft 1.0 10.0 9.5
|
|
pair_coeff * * 1.0
|
|
pair_coeff 1 1 1.0 9.5
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style tip4p/long/soft 1 2 7 8 0.15 2.0 0.5 10.0 9.8
|
|
pair_coeff * * 1.0
|
|
pair_coeff 1 1 1.0 9.5
|
|
</pre></div>
|
|
</div>
|
|
</div>
|
|
<div class="section" id="description">
|
|
<h2>Description<a class="headerlink" href="#description" title="Permalink to this headline">¶</a></h2>
|
|
<p>The <em>lj/cut/soft</em> style and substyles compute the 12/6 Lennard-Jones
|
|
and Coulomb potential modified by a soft core, in order to avoid
|
|
singularities during free energy calculations when sites are created
|
|
or anihilated <a class="reference internal" href="#beutler"><span>(Beutler)</span></a>,</p>
|
|
<img alt="_images/pair_lj_soft.jpg" class="align-center" src="_images/pair_lj_soft.jpg" />
|
|
<p>Coulomb interactions are also damped with a soft core at short
|
|
distance,</p>
|
|
<img alt="_images/pair_coul_soft.jpg" class="align-center" src="_images/pair_coul_soft.jpg" />
|
|
<p>In the Coulomb part C is an energy-conversion constant, q_i and q_j
|
|
are the charges on the 2 atoms, and epsilon is the dielectric constant
|
|
which can be set by the <a class="reference internal" href="dielectric.html"><em>dielectric</em></a> command.</p>
|
|
<p>The coefficient lambda is an activation parameter. When lambda = 1 the
|
|
pair potentiel is identical to a Lennard-Jones term or a Coulomb term
|
|
or a combination of both. When lambda = 0 the interactions are
|
|
deactivated. The transition between these two extrema is smoothed by a
|
|
soft repulsive core in order to avoid singularities in potential
|
|
energy and forces when sites are created or anihilated and can overlap
|
|
<a class="reference internal" href="#beutler"><span>(Beutler)</span></a>.</p>
|
|
<p>The paratemers n, alpha_LJ and alpha_C are set in the
|
|
<a class="reference internal" href="pair_style.html"><em>pair_style</em></a> command, before the cutoffs. Usual
|
|
choices for the exponent are n = 2 or n = 1. For the remaining
|
|
coefficients alpha_LJ = 0.5 and alpha_C = 10 Angstrom^2 are
|
|
appropriate choices. Plots of the LJ and Coulomb terms are shown
|
|
below, for lambda ranging from 1 to 0 every 0.1.</p>
|
|
<img alt="_images/lj_soft.jpg" class="align-center" src="_images/lj_soft.jpg" />
|
|
<img alt="_images/coul_soft.jpg" class="align-center" src="_images/coul_soft.jpg" />
|
|
<p>For the <em>lj/cut/coul/cut/soft</em> or <em>lj/cut/coul/long/soft</em> pair styles,
|
|
the following coefficients must be defined for each pair of atoms
|
|
types via the <a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a> command as in the examples
|
|
above, or in the data file or restart files read by the
|
|
<a class="reference internal" href="read_data.html"><em>read_data</em></a> or <a class="reference internal" href="read_restart.html"><em>read_restart</em></a>
|
|
commands, or by mixing as described below:</p>
|
|
<ul class="simple">
|
|
<li>epsilon (energy units)</li>
|
|
<li>sigma (distance units)</li>
|
|
<li>lambda (activation parameter between 0 and 1)</li>
|
|
<li>cutoff1 (distance units)</li>
|
|
<li>cutoff2 (distance units)</li>
|
|
</ul>
|
|
<p>The latter two coefficients are optional. If not specified, the global
|
|
LJ and Coulombic cutoffs specified in the pair_style command are used.
|
|
If only one cutoff is specified, it is used as the cutoff for both LJ
|
|
and Coulombic interactions for this type pair. If both coefficients
|
|
are specified, they are used as the LJ and Coulombic cutoffs for this
|
|
type pair. You cannot specify 2 cutoffs for style <em>lj/cut/soft</em>,
|
|
since it has no Coulombic terms. For the <em>coul/cut/soft</em> and
|
|
<em>coul/long/soft</em> only lambda and the optional cutoff2 are to be
|
|
specified.</p>
|
|
<p>Style <em>lj/cut/tip4p/long/soft</em> implements a soft-core version of the
|
|
TIP4P water model. The usage of this pair style is documented in the
|
|
<a class="reference internal" href="pair_lj.html"><em>pair_lj</em></a> styles. The soft-core version introduces the
|
|
lambda parameter to the list of arguments, after epsilon and sigma in
|
|
the <a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a> command. The paratemers n, alpha_LJ
|
|
and alpha_C are set in the <a class="reference internal" href="pair_style.html"><em>pair_style</em></a> command,
|
|
before the cutoffs.</p>
|
|
<p>Style <em>lj/charmm/coul/long/soft</em> implements a soft-core version of the
|
|
CHARMM version of LJ interactions with an additional switching
|
|
function S(r) that ramps the energy and force smoothly to zero between
|
|
an inner and outer cutoff. The usage of this pair style is documented
|
|
in the <a class="reference internal" href="pair_charmm.html"><em>pair_charmm</em></a> styles. The soft-core version
|
|
introduces the lambda parameter to the list of arguments, after
|
|
epsilon and sigma in the <a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a> command (and
|
|
before the optional eps14 and sigma14). The paratemers n,
|
|
alpha_LJ and alpha_C are set in the <a class="reference internal" href="pair_style.html"><em>pair_style</em></a>
|
|
command, before the cutoffs.</p>
|
|
<p>The <em>coul/cut/soft</em>, <em>coul/long/soft</em> and <em>tip4p/long/soft</em> substyles
|
|
are designed to be combined with other pair potentials via the
|
|
<a class="reference internal" href="pair_hybrid.html"><em>pair_style hybrid/overlay</em></a> command. This is because
|
|
they have no repulsive core. Hence, if used by themselves, there will
|
|
be no repulsion to keep two oppositely charged particles from
|
|
overlapping each other. In this case, if lambda = 1, a singularity may
|
|
occur. These substyles are suitable to represent charges embedded in
|
|
the Lennard-Jones radius of another site (for example hydrogen atoms
|
|
in several water models).</p>
|
|
<p>IMPORTANT NOTES: When using the core-softed Coulomb potentials with
|
|
long-range solvers (<em>coul/long/soft</em>, <em>lj/cut/coul/long/soft</em>, etc.)
|
|
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>
|
|
<hr class="docutils" />
|
|
<p><strong>Mixing, shift, tail correction, restart info</strong>:</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
|
|
similar substyle can be used via the
|
|
<a class="reference internal" href="pair_hybrid.html"><em>pair_style hybrid/overlay</em></a> command.</p>
|
|
<hr class="docutils" />
|
|
<p>All of the plain <em>soft</em> pair styles are part of the USER-FEP package.
|
|
The <em>long</em> styles also requires the KSPACE package to be installed.
|
|
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>
|
|
</div>
|
|
<div class="section" id="related-commands">
|
|
<h2>Related commands<a class="headerlink" href="#related-commands" title="Permalink to this headline">¶</a></h2>
|
|
<p><a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a>, <a class="reference internal" href="fix_adapt.html"><em>fix_adapt</em></a>,
|
|
<a class="reference internal" href="fix_adapt_fep.html"><em>fix_adapt/fep</em></a>, <a class="reference internal" href="compute_fep.html"><em>compute_fep</em></a></p>
|
|
<p><strong>Default:</strong> none</p>
|
|
<hr class="docutils" />
|
|
<p id="beutler"><strong>(Beutler)</strong> Beutler, Mark, van Schaik, Gerber, van Gunsteren, Chem
|
|
Phys Lett, 222, 529 (1994).</p>
|
|
</div>
|
|
</div>
|
|
|
|
|
|
</div>
|
|
</div>
|
|
<footer>
|
|
|
|
|
|
<hr/>
|
|
|
|
<div role="contentinfo">
|
|
<p>
|
|
© Copyright .
|
|
</p>
|
|
</div>
|
|
Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
|
|
|
|
</footer>
|
|
|
|
</div>
|
|
</div>
|
|
|
|
</section>
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
|
|
<script type="text/javascript">
|
|
var DOCUMENTATION_OPTIONS = {
|
|
URL_ROOT:'./',
|
|
VERSION:'15 May 2015 version',
|
|
COLLAPSE_INDEX:false,
|
|
FILE_SUFFIX:'.html',
|
|
HAS_SOURCE: true
|
|
};
|
|
</script>
|
|
<script type="text/javascript" src="_static/jquery.js"></script>
|
|
<script type="text/javascript" src="_static/underscore.js"></script>
|
|
<script type="text/javascript" src="_static/doctools.js"></script>
|
|
<script type="text/javascript" src="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
|
|
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2/js/jquery-1.11.0.min.js"></script>
|
|
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2/js/lightbox.min.js"></script>
|
|
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2-customize/jquery-noconflict.js"></script>
|
|
|
|
|
|
|
|
|
|
|
|
<script type="text/javascript" src="_static/js/theme.js"></script>
|
|
|
|
|
|
|
|
|
|
<script type="text/javascript">
|
|
jQuery(function () {
|
|
SphinxRtdTheme.StickyNav.enable();
|
|
});
|
|
</script>
|
|
|
|
|
|
</body>
|
|
</html> |