hi sir i have also problem of 1 negative frequency in my calculation i have tried a lot of times with different parameters<div><br /><br /></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Friday, January 27, 2017 at 12:13:21 AM UTC+8 Ali KACHMAR wrote:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr">Hi Luis,<div><br></div><div>BTW, The one water molecule is not also straight forward. But, I can assure you if you do for one water molecule you will do for 2, 3, 4 molecules.</div><div><br></div><div>Don't be surprised! Getting negative frequencies is quite common not only in cp2k, but also in other DFT codes. </div><div><br></div><div>those are the frequencies for H2O</div><div><div> 2.165588</div><div> 64.392500</div><div> 146.662981</div><div> 1613.021758</div><div> 3717.933517</div><div> 3822.394550</div></div><div><br></div><div>You are not missing anything rather than you have to insist to get converged geometries.</div><div><br></div><div>Best, Ali</div><div><div class="gmail_extra"><br><div class="gmail_quote"></div></div></div></div><div dir="ltr"><div><div class="gmail_extra"><div class="gmail_quote">On Thu, Jan 26, 2017 at 5:41 PM, Matt W <span dir="ltr"><<a href data-email-masked rel="nofollow">MattWa...@gmail.com</a>></span> wrote:<br></div></div></div></div><div dir="ltr"><div><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">What could be a harder test case than small water clusters?<div><br></div><div>Matt<span><br><br>On Thursday, January 26, 2017 at 2:38:56 PM UTC, Luis Ruiz Pestana wrote:</span><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span><div dir="ltr">Hi Ali,<div><br></div><div>Thanks for the response! I am using 400 Ry because I needed it to be the same cutoff that I used in some other AIMD simulations in the condensed phase. Regardless, I have tried the suggested changes and I still get imaginary frequencies. I am quite surprised that cp2k is having a hard time with such simple small systems, am I missing something?</div><div><br></div><div>Best,</div><div>Luis</div></div></span><div><br><div class="gmail_quote"><span>On Wed, Jan 25, 2017 at 9:35 AM, Ali KACHMAR <span dir="ltr"><<a rel="nofollow">ali.kac...@gmail.com</a>></span> wrote:<br></span><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span><div dir="ltr">Dear Luis,<div> <br></div><div>1. a cutoff of 400 Ry is a bit low for geometry optimization + vibrational frequency calculations on water systems. Please run your geometry optimization with tight convergence and a cutoff=550 Ry, Relcutoff=70 Ry</div><div><br></div><div>2. Starting from the optimized geometry, please run your vibrational analysis calculation using a DX=0.01, and add to the GEO_OPT section </div><div><br></div><div><div> &GEO_OPT</div><div> TYPE MINIMIZATION</div><div> OPTIMIZER CG</div><div> &END GEO_OPT</div><div><br></div></div><div><br></div><div>All the best,</div><div>Ali</div><div><br></div></div></span><div><br><div class="gmail_quote"><span><span>On Tue, Jan 24, 2017 at 6:00 PM, <span dir="ltr"><<a rel="nofollow">lar...@lbl.gov</a>></span> wrote:<br></span></span><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span><span><div dir="ltr">I am trying to compute the vibrational frequencies of small water clusters, and I am having trouble getting rid of imaginary frequencies, even for the water dimer, using very tight convergence parameters during the geometry optimization.I have also tried to run the simulations with periodic boundary conditions, different values of the displacement, etc., but I still get a few imaginary frequencies. I have run out of ideas to try so any advice will be greatly appreciated. I have attached here the input files of the calculations. <div><br></div><div>Thanks for your time!</div><div>Luis</div></div></span></span><span><font color="#888888"><span><font color="#888888"><span> <p></p> -- <br> You received this message because you are subscribed to the Google Groups "cp2k" group.<br></span> To unsubscribe from this group and stop receiving emails from it, send an email to <a rel="nofollow">cp2k+uns...@googlegroups.com</a>.</font></span><span><br> To post to this group, send email to <a rel="nofollow">cp...@googlegroups.com</a>.<span><br> Visit this group at <a href="https://groups.google.com/group/cp2k" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/group/cp2k&source=gmail&ust=1717236130208000&usg=AOvVaw3413jC2JgmCXS1fzI2_sG2">https://groups.google.com/group/cp2k</a>.<br> For more options, visit <a href="https://groups.google.com/d/optout" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/optout&source=gmail&ust=1717236130208000&usg=AOvVaw3qyGm8HYtYZ_SayosGpCp1">https://groups.google.com/d/optout</a>.<br> </span></span></font></span></blockquote></div><br></div><div><div><span> <p></p> -- <br> You received this message because you are subscribed to a topic in the Google Groups "cp2k" group.<br> To unsubscribe from this topic, visit <a href="https://groups.google.com/d/topic/cp2k/F42_Nn9BqYg/unsubscribe" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/topic/cp2k/F42_Nn9BqYg/unsubscribe&source=gmail&ust=1717236130208000&usg=AOvVaw0m7KuoENi7BTOmOUkwgWDa">https://groups.google.com/d/topic/cp2k/F42_Nn9BqYg/unsubscribe</a>.<br></span> To unsubscribe from this group and all its topics, send an email to <a rel="nofollow">cp2k+uns...@googlegroups.com</a>.<br> To post to this group, send email to <a rel="nofollow">cp...@googlegroups.com</a>.<span><br> Visit this group at <a href="https://groups.google.com/group/cp2k" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/group/cp2k&source=gmail&ust=1717236130208000&usg=AOvVaw3413jC2JgmCXS1fzI2_sG2">https://groups.google.com/group/cp2k</a>.<br> For more options, visit <a href="https://groups.google.com/d/optout" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/optout&source=gmail&ust=1717236130208000&usg=AOvVaw3qyGm8HYtYZ_SayosGpCp1">https://groups.google.com/d/optout</a>.<br> </span></div></div></blockquote></div><span><br><br clear="all"><div><br></div>-- <br><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><span style="color:rgb(136,136,136);font-size:12.8000001907349px">Luis A. Ruiz Pestana, PhD</span><div style="color:rgb(136,136,136);font-size:12.8000001907349px">Postdoctoral Fellow</div><div style="color:rgb(136,136,136);font-size:12.8000001907349px">University of California, Berkeley</div><div style="color:rgb(136,136,136);font-size:12.8000001907349px">Lawrence Berkeley National Laboratory</div><div style="color:rgb(136,136,136);font-size:12.8000001907349px">Berkeley, CA 94720</div></div></div></div></div></div></div></div> </span></div> </blockquote></div></div></blockquote></div></div></div></div><div dir="ltr"><div><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div><div> <p></p> -- <br> You received this message because you are subscribed to the Google Groups "cp2k" group.<br></div></div></blockquote></div></div></div></div><div dir="ltr"><div><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div><div> To unsubscribe from this group and stop receiving emails from it, send an email to <a href data-email-masked rel="nofollow">cp2k+unsubscribe@googlegroups.com</a>.</div></div></blockquote></div></div></div></div><div dir="ltr"><div><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div><div><br> To post to this group, send email to <a href data-email-masked rel="nofollow">cp...@googlegroups.com</a>.<br> Visit this group at <a href="https://groups.google.com/group/cp2k" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/group/cp2k&source=gmail&ust=1717236130208000&usg=AOvVaw3413jC2JgmCXS1fzI2_sG2">https://groups.google.com/group/cp2k</a>.<br> For more options, visit <a href="https://groups.google.com/d/optout" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/d/optout&source=gmail&ust=1717236130208000&usg=AOvVaw3qyGm8HYtYZ_SayosGpCp1">https://groups.google.com/d/optout</a>.<br> </div></div></blockquote></div></div></div></div></blockquote></div> <p></p> -- <br /> You received this message because you are subscribed to the Google Groups "cp2k" group.<br /> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>.<br /> To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/291c6767-92c2-459a-9139-e9a5bdedbafen%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/291c6767-92c2-459a-9139-e9a5bdedbafen%40googlegroups.com</a>.<br />