<span id="result_box" class="" lang="en"><span class="hps">I am using</span> <span class="hps">cp2k</span> <span class="hps">for simulating</span> <span class="hps">vibrational spectra</span> <span class="hps">in the solid state</span><span class="">,</span> <span class="hps">but I'm</span> <span class="hps">optimizing the</span> <span class="hps">crystal structures</span><span class="">.</span> <span class="hps">My question</span> <span class="hps">is</span> <span class="hps">about the</span> <span class="hps">convergence criteria</span> <span class="hps">RMS</span> <span class="hps">gradient.</span> <span class="hps">Default</span> <span class="hps">is</span> <span class="hps">3x10</span><span class="atn">-</span><span class="">4</span><span class="">,</span> <span class="hps">but I'm used</span> <span class="hps">1x10</span><span class="atn">-</span><span class="">6</span><span class="">.</span> <span class="hps">The problem</span> <span class="hps">is the delay</span> <span class="hps">in the calculation</span><span class="">,</span> <span class="hps">I want to avoid</span> <span class="hps">the presence of</span> <span class="hps">imaginary</span> <span class="hps">frequencies</span><span class="">.</span><br><span class="hps">Someone</span> <span class="hps">could indicate</span> <span class="hps">their</span> <span class="hps">experiences</span><span class="">?</span></span>