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@ -136,7 +136,7 @@
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<li>chunk/atom = style name of this compute command</li>
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</ul>
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<pre class="literal-block">
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style = <em>bin/1d</em> or <em>bin/2d</em> or <em>bin/3d</em> or <em>type</em> or <em>molecule</em> or <em>compute/fix/variable</em>
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style = <em>bin/1d</em> or <em>bin/2d</em> or <em>bin/3d</em> or <em>bin/sphere</em> or <em>type</em> or <em>molecule</em> or <em>compute/fix/variable</em>
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<em>bin/1d</em> args = dim origin delta
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dim = <em>x</em> or <em>y</em> or <em>z</em>
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origin = <em>lower</em> or <em>center</em> or <em>upper</em> or coordinate value (distance units)
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@ -149,6 +149,10 @@ style = <em>bin/1d</em> or <em>bin/2d</em> or <em>bin/3d</em> or <em>type</em> o
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dim = <em>x</em> or <em>y</em> or <em>z</em>
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origin = <em>lower</em> or <em>center</em> or <em>upper</em> or coordinate value (distance units)
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delta = thickness of spatial bins in dim (distance units)
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<em>bin/sphere</em> args = xorig yorig zorig rmin rmax nrbin
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xorig,yorig,zorig = center point of sphere
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rmin,rmax = bin from radius rmin to rmax
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nrbin = # of bins between rmin and rmax
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<em>type</em> args = none
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<em>molecule</em> args = none
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<em>compute/fix/variable</em> = c_ID, c_ID[I], f_ID, f_ID[I], v_name with no args
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@ -14,7 +14,7 @@ compute ID group-ID chunk/atom style args keyword values ... :pre
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ID, group-ID are documented in "compute"_compute.html command :ulb,l
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chunk/atom = style name of this compute command :l
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style = {bin/1d} or {bin/2d} or {bin/3d} or {type} or {molecule} or {compute/fix/variable}
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style = {bin/1d} or {bin/2d} or {bin/3d} or {bin/sphere} or {type} or {molecule} or {compute/fix/variable}
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{bin/1d} args = dim origin delta
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dim = {x} or {y} or {z}
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origin = {lower} or {center} or {upper} or coordinate value (distance units)
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@ -27,6 +27,10 @@ style = {bin/1d} or {bin/2d} or {bin/3d} or {type} or {molecule} or {compute/fix
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dim = {x} or {y} or {z}
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origin = {lower} or {center} or {upper} or coordinate value (distance units)
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delta = thickness of spatial bins in dim (distance units)
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{bin/sphere} args = xorig yorig zorig rmin rmax nrbin
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xorig,yorig,zorig = center point of sphere
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rmin,rmax = bin from radius rmin to rmax
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nrbin = # of bins between rmin and rmax
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{type} args = none
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{molecule} args = none
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{compute/fix/variable} = c_ID, c_ID\[I\], f_ID, f_ID\[I\], v_name with no args
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@ -150,7 +150,7 @@ fix 1 all drude/transform/inverse
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<h2>Description<a class="headerlink" href="#description" title="Permalink to this headline">¶</a></h2>
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<p>Transform the coordinates of Drude oscillators from real to reduced
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and back for thermalizing the Drude oscillators as described in
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<a class="reference internal" href="#lamoureux"><span>(Lamoureux)</span></a> using a Nose-Hoover thermostat. This fix is
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<a class="reference internal" href="tutorial_drude.html#lamoureux"><span>(Lamoureux)</span></a> using a Nose-Hoover thermostat. This fix is
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designed to be used with the <a class="reference internal" href="tutorial_drude.html"><em>thermalized Drude oscillator model</em></a>. Polarizable models in LAMMPS are
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described in <a class="reference internal" href="Section_howto.html#howto-25"><span>this Section</span></a>.</p>
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<p>Drude oscillators are a pair of atoms representing a single
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@ -158,7 +158,7 @@ fix 1 all langevin/drude 298.15 100.0 19377 5.0 10.0 83451 zero yes
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</div>
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<div class="section" id="description">
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<h2>Description<a class="headerlink" href="#description" title="Permalink to this headline">¶</a></h2>
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<p>Apply two Langevin thermostats as described in <a class="reference internal" href="#jiang"><span>(Jiang)</span></a> for
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<p>Apply two Langevin thermostats as described in <a class="reference internal" href="tutorial_drude.html#jiang"><span>(Jiang)</span></a> for
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thermalizing the reduced degrees of freedom of Drude oscillators.
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This link describes how to use the <a class="reference internal" href="tutorial_drude.html"><em>thermalized Drude oscillator model</em></a> in LAMMPS and polarizable models in LAMMPS
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are discussed in <a class="reference internal" href="Section_howto.html#howto-25"><span>this Section</span></a>.</p>
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@ -158,28 +158,30 @@ main pair style including Coulomb interactions, i.e. any pair style
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containing <em>coul/cut</em> or <em>coul/long</em> in its style name.</p>
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<p>The <em>thole</em> pair style computes the Coulomb interaction damped at
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short distances by a function</p>
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<p>begin{equation} T_{ij}(r_{ij}) = 1 - left( 1 +
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frac{s_{ij} r_{ij} }{2} right)
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exp left( - s_{ij} r_{ij} right) end{equation}</p>
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<div class="math">
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\[\begin{equation} T_{ij}(r_{ij}) = 1 - \left( 1 +
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\frac{s_{ij} r_{ij} }{2} \right)
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\exp \left( - s_{ij} r_{ij} \right) \end{equation}\]</div>
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<p>This function results from an adaptation to point charges
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<a class="reference internal" href="#noskov"><span>(Noskov)</span></a> of the dipole screening scheme originally proposed
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by <a class="reference internal" href="#thole"><span>Thole</span></a>. The scaling coefficient (s_{ij} ) is determined
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by the polarizability of the atoms, ( alpha_i ), and by a Thole
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damping parameter ( a ). This Thole damping parameter usually takes
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by <a class="reference internal" href="#thole"><span>Thole</span></a>. The scaling coefficient <span class="math">\(s_{ij}\)</span> is determined
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by the polarizability of the atoms, <span class="math">\(\alpha_i\)</span>, and by a Thole
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damping parameter <span class="math">\(a\)</span>. This Thole damping parameter usually takes
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a value of 2.6, but in certain force fields the value can depend upon
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the atom types. The mixing rule for Thole damping parameters is the
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arithmetic average, and for polarizabilities the geometric average
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between the atom-specific values.</p>
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<p>begin{equation} s_{ij} = frac{ a_{ij} }{
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(alpha_{ij})^{1/3} } = frac{ (a_i + a_j)/2 }{
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[(alpha_ialpha_j)^{1/2}]^{1/3} } end{equation}</p>
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<div class="math">
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\[\begin{equation} s_{ij} = \frac{ a_{ij} }{
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(\alpha_{ij})^{1/3} } = \frac{ (a_i + a_j)/2 }{
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[(\alpha_i\alpha_j)^{1/2}]^{1/3} } \end{equation}\]</div>
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<p>The damping function is only applied to the interactions between the
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point charges representing the induced dipoles on polarizable sites,
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that is, charges on Drude particles, ( q_{D,i} ), and opposite
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charges, ( -q_{D,i} ), located on the respective core particles
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that is, charges on Drude particles, <span class="math">\(q_{D,i}\)</span>, and opposite
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charges, <span class="math">\(-q_{D,i}\)</span>, located on the respective core particles
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(to which each Drude particle is bonded). Therefore, Thole screening
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is not applied to the full charge of the core particle ( q_i ), but
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only to the ( -q_{D,i} ) part of it.</p>
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is not applied to the full charge of the core particle <span class="math">\(q_i\)</span>, but
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only to the <span class="math">\(-q_{D,i}\)</span> part of it.</p>
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<p>The interactions between core charges are subject to the weighting
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factors set by the <a class="reference internal" href="special_bonds.html"><em>special_bonds</em></a> command. The
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interactions between Drude particles and core charges or
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