<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Thanks again. I’ve already looked through that section, it seems to be what I need. I’ll check the source file to make sure that I understand things correctly.<div class=""><br class=""></div><div class="">Appreciate your help.</div><div class=""><br class=""></div><div class="">Best regards,</div><div class="">Roman Dmitriev.<br class=""><div class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Jun 30, 2018, at 2:05 PM, Matt W <<a href="mailto:mattwa...@gmail.com" class="">mattwa...@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Look in qs_external_potential.F for the code.<br class=""><br class="">It is quite flexible. You can supply a function in analytic form in this <a href="https://manual.cp2k.org/cp2k-5_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/EXTERNAL_POTENTIAL.html" class="">section</a>. You should be able to set up a periodic external potential without any coding, I think.<div class=""><br class=""></div><div class="">Matt <br class=""><br class="">On Saturday, June 30, 2018 at 8:00:12 PM UTC+1, NGastaPooh wrote:<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><div style="word-wrap:break-word;line-break:after-white-space" class="">Hello Matt,<div class=""><br class=""></div><div class="">Thank you very much for your answer. I want to periodically shift electronic charge density throughout a periodic solid to create a charge density "wave". The next step would be to observe the effect of such density change on a band structure of the solid. <br class=""><div class=""><br class=""></div><div class="">As far as I understood from your answer, the only way is to go with external potential. Does it sound right? If so, could you please direct me to the source file for it?</div><div class=""><br class=""></div><div class="">Thanks in advance.</div><div class=""><br class=""></div><div class="">Best regards,</div><div class="">Roman Dmitriev.</div><div class=""><blockquote type="cite" class=""><div class="">On Jun 30, 2018, at 10:42 AM, Matt W <<a target="_blank" gdf-obfuscated-mailto="GyQCW2C1CQAJ" rel="nofollow" class="">matt...@gmail.com</a>> wrote:</div><br class=""><div class=""><div dir="ltr" class="">Hi,<div class=""><br class=""></div><div class="">there are, in principle, several ways of applying an electric field. The only way that makes proper sense for a periodic solid is the <a href="https://manual.cp2k.org/cp2k-5_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/PERIODIC_EFIELD.html" target="_blank" rel="nofollow" class="">periodic efield</a><br class="">. I would be (very) surprised if it works with k-points. The main methods are in qs_efield_berry.F. </div><div class=""><br class=""></div><div class="">See </div><div class=""><br class=""></div><div class=""> Stengel, Massimiliano; Spaldin, Nicola A.; Vanderbilt, David. </div><div class=""> NATURE PHYSICS, 5 (4), 304-308 (2009). </div><div class=""> Ab initio molecular dynamics in a finite homogeneous electric field</div><div class=""> Electric displacement as the fundamental variable in</div><div class=""> electronic-structure calculations.</div><div class=""> <a href="http://dx.doi.org/10.1038/NPHYS1185" target="_blank" rel="nofollow" class="">http://dx.doi.org/10.1038/<wbr class="">NPHYS1185</a></div><div class=""><br class=""></div><div class="">and</div><div class=""><br class=""></div><div class=""><span style="font-family:Arial,sans-serif" class="">Zhang, Chao, Jürg Hutter, and Michiel Sprik. "Computing the Kirkwood g-Factor by combining constant maxwell electric field and electric displacement simulations: application to the dielectric constant of liquid water." </span><i style="font-family:Arial,sans-serif" class="">The journal of physical chemistry letters</i><span style="font-family:Arial,sans-serif" class=""> 7.14 (2016): 2696-2701.</span><br class=""></div><div class=""><br class=""></div><div class="">There is also a non periodic version that might be easier to follow (efield_utils.F) and a general external potential that could be applied. Depends what you want to do.</div><div class=""><br class=""></div><div class="">Matt</div><div class=""> <br class="">On Thursday, June 28, 2018 at 11:17:33 PM UTC+1, NGastaPooh wrote:<blockquote class="gmail_quote" style="margin:0;margin-left:0.8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" class=""><span style="font-size:12px" class="">Dear All,</span><span style="font-family:Helvetica;font-size:12px" class=""></span><div style="font-size:12px" class=""><br class=""></div><div style="font-size:12px" class="">I need to utilize the ability of CP2K to subject the electrons to an externally imposed electric </div><div style="font-size:12px" class="">field but am not sure as to exactly how this is implemented in the code. I would greatly appreciate </div><div style="font-size:12px" class="">it, if anyone could provide me with some details or direct me to the sub-routine that accounts for the external potential implementation.</div><div style="font-size:12px" class=""><br class=""></div><div style="font-size:12px" class="">I also have a separate question: what are the energy units in BAND_STRUCTURE routine output file? </div><div style="font-size:12px" class=""><br class=""></div><div style="font-size:12px" class="">Thank you in advance.</div><div style="font-size:12px" class=""><br class=""></div><div style="font-size:12px" class="">Best regards,</div><div style="font-size:12px" class="">Roman Dmitriev</div></div></blockquote></div></div><div class=""><br class=""></div> -- <br class=""> You received this message because you are subscribed to a topic in the Google Groups "cp2k" group.<br class=""> To unsubscribe from this topic, visit <a href="https://groups.google.com/d/topic/cp2k/1shC8Lc39_c/unsubscribe" target="_blank" rel="nofollow" class="">https://groups.google.com/d/<wbr class="">topic/cp2k/1shC8Lc39_c/<wbr class="">unsubscribe</a>.<br class=""> To unsubscribe from this group and all its topics, send an email to <a target="_blank" gdf-obfuscated-mailto="GyQCW2C1CQAJ" rel="nofollow" class="">cp2k+uns...@googlegroups.<wbr class="">com</a>.<br class=""> To post to this group, send email to <a target="_blank" gdf-obfuscated-mailto="GyQCW2C1CQAJ" rel="nofollow" class="">cp...@googlegroups.com</a>.<br class=""> Visit this group at <a href="https://groups.google.com/group/cp2k" target="_blank" rel="nofollow" class="">https://groups.google.com/<wbr class="">group/cp2k</a>.<br class=""> For more options, visit <a href="https://groups.google.com/d/optout" target="_blank" rel="nofollow" class="">https://groups.google.com/d/<wbr class="">optout</a>.<br class=""> </div></blockquote></div><br class=""></div></div></blockquote></div></div><div class=""><br class="webkit-block-placeholder"></div> -- <br class=""> You received this message because you are subscribed to a topic in the Google Groups "cp2k" group.<br class=""> To unsubscribe from this topic, visit <a href="https://groups.google.com/d/topic/cp2k/1shC8Lc39_c/unsubscribe" class="">https://groups.google.com/d/topic/cp2k/1shC8Lc39_c/unsubscribe</a>.<br class=""> To unsubscribe from this group and all its topics, send an email to <a href="mailto:cp2k+uns...@googlegroups.com" class="">cp2k+uns...@googlegroups.com</a>.<br class=""> To post to this group, send email to <a href="mailto:cp...@googlegroups.com" class="">cp...@googlegroups.com</a>.<br class=""> Visit this group at <a href="https://groups.google.com/group/cp2k" class="">https://groups.google.com/group/cp2k</a>.<br class=""> For more options, visit <a href="https://groups.google.com/d/optout" class="">https://groups.google.com/d/optout</a>.<br class=""> </div></blockquote></div><br class=""></div></div></body></html>