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Copy file name to clipboardExpand all lines: sphinx/build/html/tutorial5/reactive-silicon-dioxide.html
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@@ -328,7 +328,7 @@ <h2>Prepare and relax<a class="headerlink" href="#prepare-and-relax" title="Link
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personalized <ahref="https://www.patreon.com/molecularsimulations" target="_blank">advice</a> for your project.</p>
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</div>
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<p>The initial topology given by <ahref="https://raw.githubusercontent.com/lammpstutorials/lammpstutorials-inputs/refs/heads/main/tutorial5/silica.data" target="_blank">silica.data</a>
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is a small amorphous silica structure. This structure was generated in a prior
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corresponds to a small amorphous silica structure. This structure was generated in a prior
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simulation using the Vashishta force field <spanid="id3">[<aclass="reference internal" href="../non-tutorials/bibliography.html#id50" title="P Vashishta, Rajiv K Kalia, José P Rino, and Ingvar Ebbsjö. Interaction potential for SiO2: a molecular-dynamics study of structural correlations. Physical Review B, 41(17):12197, 1990.">41</a>]</span>.
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If you open the <strong>silica.data</strong>
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file, you will find in the <codeclass="docutils literal notranslate"><spanclass="pre">Atoms</span></code> section that all silicon atoms have a
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<p>Assigning the same charge to all atoms of the same type is common with many
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force fields, including the force fields used in the previous tutorials. This
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changes once ReaxFF is used: the charge of each atom will adjust to its local
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environment.</p>
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environment through charge equilibration.</p>
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</div>
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<p>Next, copy the following three crucial lines into the <strong>relax.lmp</strong> file:</p>
<p>In this case, the <codeclass="docutils literal notranslate"><spanclass="pre">pair_style</span><spanclass="pre">reaxff</span></code> is used without a control file. The
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<p>In this case, the <codeclass="docutils literal notranslate"><spanclass="pre">pair_style</span><spanclass="pre">reaxff</span></code> is used without a control file (see note below). The
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<codeclass="docutils literal notranslate"><spanclass="pre">safezone</span></code> and <codeclass="docutils literal notranslate"><spanclass="pre">mincap</span></code> keywords are added to prevent
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allocation issues, which sometimes can trigger segmentation faults and
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<codeclass="docutils literal notranslate"><spanclass="pre">bondchk</span></code> errors. The <codeclass="docutils literal notranslate"><spanclass="pre">pair_coeff</span></code> command uses the <ahref="https://raw.githubusercontent.com/lammpstutorials/lammpstutorials-inputs/refs/heads/main/tutorial5/ffield.reax.CHOFe" target="_blank">ffield.reax.CHOFe</a>
@@ -375,7 +375,11 @@ <h2>Prepare and relax<a class="headerlink" href="#prepare-and-relax" title="Link
<p>To print the averaged charges <codeclass="docutils literal notranslate"><spanclass="pre">qSi</span></code> and <codeclass="docutils literal notranslate"><spanclass="pre">qO</span></code> using the
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<p>The definition of the equal style variables qSi and qO make
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use of functions pre-defined within LAMMPS that allow
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calculating the total charge of atoms belonging to a group
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(<codeclass="docutils literal notranslate"><spanclass="pre">charge()</span></code>) and the total number of atoms in the group
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(<codeclass="docutils literal notranslate"><spanclass="pre">count()</span></code>). To print the averaged charges <codeclass="docutils literal notranslate"><spanclass="pre">qSi</span></code> and <codeclass="docutils literal notranslate"><spanclass="pre">qO</span></code> using the
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<codeclass="docutils literal notranslate"><spanclass="pre">thermo_style</span></code> command, and create images of the system. Add the
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following lines to <strong>relax.lmp</strong>:</p>
@@ -434,7 +438,9 @@ <h2>Prepare and relax<a class="headerlink" href="#prepare-and-relax" title="Link
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box can change independently. This is particularly relevant for solids and other
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systems where anisotropic stresses may develop.</p>
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</div>
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<p>Run the <strong>relax.lmp</strong> file using LAMMPS. As seen from <strong>relax.species</strong>,
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<p>The <codeclass="docutils literal notranslate"><spanclass="pre">write_data</span></code> command is used with the nofix keyword to print a data file
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without extra sections from the <codeclass="docutils literal notranslate"><spanclass="pre">reaxff/species</span></code> command.
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Run the <strong>relax.lmp</strong> file using LAMMPS. As seen from <strong>relax.species</strong>,
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only one species is detected, called <codeclass="docutils literal notranslate"><spanclass="pre">O384Si192</span></code>, representing the entire system.</p>
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<p>As the simulation progresses, the charge of every atom fluctuates
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because it is adjusting to the local environment of the atom.
@@ -529,7 +535,7 @@ <h3>Deform the structure<a class="headerlink" href="#deform-the-structure" title
<p>Here, the <spanclass="math notranslate nohighlight">\(+1 \mathrm{e}{-10}\)</span> was added to the denominator of the <codeclass="docutils literal notranslate"><spanclass="pre">variable</span><spanclass="pre">qH</span></code>
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to avoid dividing by 0 at the beginning of the simulation. Finally, let us
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create a loop with 10 steps, and create two hydrogen atoms at random locations at
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every step:</p>
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<p>The commands above are, once again, similar to the ones of the previous script.
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Here, the <spanclass="math notranslate nohighlight">\(+1 \mathrm{e}{-10}\)</span> was added to the denominator of the <codeclass="docutils literal notranslate"><spanclass="pre">variable</span><spanclass="pre">qH</span></code>
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to avoid dividing by 0 at the beginning of the simulation, as no hydrogen atoms exists in
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the simulation domain yet. Finally, let us create a loop with 10 steps, and
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create two hydrogen atoms at random locations at every step:</p>
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