class="reference internal" href="#introduction">Introduction</a></li>
<li><a class="reference internal" href="#electronic-state-approximations">Electronic State Approximations</a><ul>
<li><a class="reference internal" href="#bloch-states">Bloch States</a><ul>
<li><a class="reference internal" href="#bloch-pw-basis-plane-wave-pw-basis"><code class="code docutils literal notranslate"><span class="pre">bloch/PW_basis</span></code>: Plane Wave (PW) basis</a></li>
<li><a class="reference internal" href="#bloch-s