<div dir="ltr">Hi Krack,<div> Thank you very much for your comment. Yeah, I just need to do a test to calculate vibrational density of state for a single water molecule. Could I just do a NVE simulation fo a single water molecule.</div><div> With my best regards,</div><div> Junbo</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Krack Matthias (PSI) <<a href="mailto:matthi...@psi.ch">matthi...@psi.ch</a>> 于2021年1月15日周五下午10:13写道：<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> <div lang="EN-US"> <div class="gmail-m_-5352925806086127062WordSection1"> <p class="MsoNormal"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Hi<u></u><u></u></span></p> <p class="MsoNormal"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p> <p class="MsoNormal"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">A single water molecule has only a few degrees of freedoms which results in large temperature fluctuations when potential energy is transferred to kinetic energy. Try a larger water sample, e.g. 32 molecules, since these fluctuations should average out more and more for larger systems.<u></u><u></u></span></p> <p class="MsoNormal"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p> <p class="MsoNormal"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Matthias<u></u><u></u></span></p> <p class="MsoNormal"><span style="font-size:11pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><u></u> <u></u></span></p> <p class="MsoNormal"><b><span lang="DE" style="font-size:11pt;font-family:Calibri,sans-serif">Von:</span></b><span lang="DE" style="font-size:11pt;font-family:Calibri,sans-serif"> <a href="mailto:cp...@googlegroups.com" target="_blank">cp...@googlegroups.com</a> <<a href="mailto:cp...@googlegroups.com" target="_blank">cp...@googlegroups.com</a>> <b>Im Auftrag von </b>Junbo Lu<br> <b>Gesendet:</b> Freitag, 15. Januar 2021 13:03<br> <b>An:</b> cp2k <<a href="mailto:cp...@googlegroups.com" target="_blank">cp...@googlegroups.com</a>><br> <b>Betreff:</b> [CP2K:14555] AIMD simulation of a single water molecule<u></u><u></u></span></p> <p class="MsoNormal"><u></u> <u></u></p> <p class="MsoNormal">Hi,<u></u><u></u></p> <div> <p class="MsoNormal"> I am trying to use CP2K to run NVT simulation for a single water molecule. But I find that the temperature fluctuates seriously. I can not get equilibrium temperature. I set the temprature as 300 K in the input file. But the temperatures in energy file are:<u></u><u></u></p> </div> <div> <p class="MsoNormal">......<u></u><u></u></p> </div> <div> <div> <p class="MsoNormal"> 3070 1535.000000 0.002485140 523.162866214<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3071 1535.500000 0.002714404 571.426577303<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3072 1536.000000 0.003027088 637.251846392<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3073 1536.500000 0.003313526 697.551698813<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3074 1537.000000 0.003476351 731.829047391<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3075 1537.500000 0.003472049 730.923409677<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3076 1538.000000 0.003333209 701.695321066<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3077 1538.500000 0.003153364 663.834925398<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3078 1539.000000 0.003034701 638.854429382<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3079 1539.500000 0.003026153 637.054856190<u></u><u></u></p> </div> <div> <p class="MsoNormal"> 3080 1540.000000 0.003093963 651.330091922<u></u><u></u></p> </div> </div> <div> <p class="MsoNormal">......<u></u><u></u></p> </div> <div> <p class="MsoNormal"> The last column is temperature. Could anyone help me? I would be very appreciated!<u></u><u></u></p> </div> <div> <p class="MsoNormal"> With my best regards,<u></u><u></u></p> </div> <div> <p class="MsoNormal"> Junbo<u></u><u></u></p> </div> <div> <p class="MsoNormal"><u></u> <u></u></p> </div> <div> <p class="MsoNormal"><u></u> <u></u></p> </div> <p class="MsoNormal">-- <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:cp...@googlegroups.com" target="_blank">cp...@googlegroups.com</a>.<br> To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/6f6edb5b-e3ee-4d3a-a576-07d9cb09da5en%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank"> https://groups.google.com/d/msgid/cp2k/6f6edb5b-e3ee-4d3a-a576-07d9cb09da5en%40googlegroups.com</a>.<u></u><u></u></p> </div> </div> <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/Jk8x8mL-tvo/unsubscribe" target="_blank">https://groups.google.com/d/topic/cp2k/Jk8x8mL-tvo/unsubscribe</a>.<br> To unsubscribe from this group and all its topics, send an email to <a href="mailto:cp...@googlegroups.com" target="_blank">cp...@googlegroups.com</a>.<br> To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/cbb6eaceff7841c5860ea2286049afbe%40psi.ch?utm_medium=email&utm_source=footer" target="_blank">https://groups.google.com/d/msgid/cp2k/cbb6eaceff7841c5860ea2286049afbe%40psi.ch</a>.<br> </blockquote></div>