<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta name="Generator" content="Microsoft Word 15 (filtered medium)"> <style></style> </head> <body lang="en-CH" link="blue" vlink="purple" style="word-wrap:break-word"> <div class="WordSection1"> <p class="MsoNormal"><span lang="DE-CH" style="font-size:11.0pt;mso-fareast-language:EN-US">Dear Léon<o:p></o:p></span></p> <p class="MsoNormal"><span lang="DE-CH" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Using a MASSIVE CSVR thermostat with a small TIMECON of about 50 is appropriate and efficient for equilibration. Thereafter, the TIMECON for the thermostat can be increased to 500-1000 for the sampling (production) runs and also a GLOBAL instead of a MASSIVE thermostat can be used, if possible, to reduce the impact of the thermostat on the dynamics. You will find different opinions about the absolute and relative values for the TIMECONs of thermostat and barostat in the web or literature. I suggest to use a two to five times larger TIMECON for the barostat compared to the thermostat. You have, however, to keep in mind that the appropriate (best) parameters for baro- and thermostat depend on the type of system and the selected conditions eventually.<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">HTH<o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US">Matthias <o:p></o:p></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p> <div id="mail-editor-reference-message-container"> <div> <div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm"> <p class="MsoNormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:36.0pt"> <b><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;color:black">From: </span></b><span style="font-size:12.0pt;font-family:"Aptos",sans-serif;color:black">cp2k@googlegroups.com <cp2k@googlegroups.com> on behalf of Léon Luntadila Lufungula <Leon.luntadilalufungula@uantwerpen.be><br> <b>Date: </b>Tuesday, 23 January 2024 at 11:47<br> <b>To: </b>cp2k <cp2k@googlegroups.com><br> <b>Subject: </b>Re: [CP2K:19801] Cons. Qty for different ensembles + Pressure fluctuation<o:p></o:p></span></p> </div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">Hi Matthias,<o:p></o:p></span></p> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"><o:p> </o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">So I started an NpT directly from the inputs you gave me with a box containing 216 water molecules. After a 300ps equilibration (plots thus starrt at 0.3 ns), the pressure fluctuations are again in the 10kbar range which is okay as you pointed out, while the average pressure is around -14 bar, so tha'ts also within the 20 bar range you mentioned. The energy drift per atom is also below 1K so everything seems to work reasonably. <o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"><o:p> </o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"><img width="1490" height="1789" style="width:15.5208in;height:18.6354in" id="_x0000_i1025" src="cid:dac9197f-4388-4dcc-bd2a-ecdcaa1651a3"><br> I'm starting my AIMD simulations as we speak, so hopefully all goes well there too. I read that it is best to do a short equilibration with a strong coupling to the thermostat (e.g. CSVR, TIMECON 20 and REGION MASSIVE), before going to a weaker coupling (e.g. CSVR, TIMECON 200 and REGION GLOBAL), but is there also a rule of thumb w.r.t. the barostat TIMECON? I regularly see TIMECON 1000, but is it useful to set it to TIMECON 100 in this early equilibration?<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"><o:p> </o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">Thanks for all the help already, it really helps me a lot given the fact that I don't have a senior researcher with a lot of hands-on CP2K experience around!<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"><o:p> </o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">Kind regards,<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">Léon<o:p></o:p></span></p> </div> <p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p> </div> </div> </div> </body> </html> <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/ZRAP278MB082700BA781DD931F3D835D0F4742%40ZRAP278MB0827.CHEP278.PROD.OUTLOOK.COM?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/ZRAP278MB082700BA781DD931F3D835D0F4742%40ZRAP278MB0827.CHEP278.PROD.OUTLOOK.COM</a>.<br />