lammps/doc/angle_sdk.html

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<div class="section" id="angle-style-sdk-command">
<span id="index-0"></span><h1>angle_style sdk command<a class="headerlink" href="#angle-style-sdk-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>angle_style sdk
</pre></div>
</div>
<div class="highlight-python"><div class="highlight"><pre>angle_style sdk/omp
</pre></div>
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</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>angle_style sdk
angle_coeff 1 300.0 107.0
</pre></div>
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<div class="section" id="description">
<h2>Description<a class="headerlink" href="#description" title="Permalink to this headline"></a></h2>
<p>The <em>sdk</em> angle style is a combination of the harmonic angle potential,</p>
<img alt="_images/angle_harmonic.jpg" class="align-center" src="_images/angle_harmonic.jpg" />
<p>where theta0 is the equilibrium value of the angle and K a prefactor,
with the <em>repulsive</em> part of the non-bonded <em>lj/sdk</em> pair style
between the atoms 1 and 3. This angle potential is intended for
coarse grained MD simulations with the CMM parametrization using the
<a class="reference internal" href="pair_sdk.html"><em>pair_style lj/sdk</em></a>. Relative to the pair_style
<em>lj/sdk</em>, however, the energy is shifted by <em>epsilon</em>, to avoid sudden
jumps. Note that the usual 1/2 factor is included in K.</p>
<p>The following coefficients must be defined for each angle type via the
<a class="reference internal" href="angle_coeff.html"><em>angle_coeff</em></a> command as in the example above:</p>
<ul class="simple">
<li>K (energy/radian^2)</li>
<li>theta0 (degrees)</li>
</ul>
<p>Theta0 is specified in degrees, but LAMMPS converts it to radians
internally; hence the units of K are in energy/radian^2.
The also required <em>lj/sdk</em> parameters will be extracted automatically
from the pair_style.</p>
</div>
<div class="section" id="restrictions">
<h2>Restrictions<a class="headerlink" href="#restrictions" title="Permalink to this headline"></a></h2>
<p>This angle style can only be used if LAMMPS was built with the
USER-CG-CMM package. See the <a class="reference internal" href="Section_start.html#start-3"><span>Making LAMMPS</span></a> section for more info on packages.</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="angle_coeff.html"><em>angle_coeff</em></a>, <a class="reference internal" href="angle_harmonic.html"><em>angle_style harmonic</em></a>, <a class="reference internal" href="pair_sdk.html"><em>pair_style lj/sdk</em></a>,
<a class="reference internal" href="pair_sdk.html"><em>pair_style lj/sdk/coul/long</em></a></p>
<p><strong>Default:</strong> none</p>
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