<div dir="ltr">I'm not sure I follow the question - the force printed out by the &MOTION section is the "mixed" force. The force on the MM atoms should be independent of the buffer radius. The force on the dynamical QM region atoms will change as you change the buffer radius, and hopefully approach some converged value. I believe that the &PRINT subsection of the &QMMM&FORCE_MIXING section should print out information as to which atoms are MM and QM, but I've forgotten the precise syntax, but you can also tell by seeing which forces vary when you change the buffer radius, and which do not.<div><br></div><div> Noam<br><div><br></div><div> Noam</div></div></div><br><div class="gmail_quote"><div dir="ltr">On Wed, Jan 2, 2019 at 8:44 AM Wei Zhang <<a href="mailto:zwei88...@gmail.com">zwei88...@gmail.com</a>> wrote:<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 dir="ltr">Deal all,<div>I would like to use the Ad buffer QM/MM method to calculate the free energy. And as mentioned in "<span style="color:rgb(0,0,0);font-family:"Microsoft YaHei",Arial,Helvetica,sans-serif;font-size:14px">The adaptive buffered force QM/MM method in the CP2K and AMBER software packages." </span><i style="color:rgb(0,0,0);font-family:"Microsoft YaHei",Arial,Helvetica,sans-serif;font-size:14px">Journal of Computational Chemistry</i><span style="color:rgb(0,0,0);font-family:"Microsoft YaHei",Arial,Helvetica,sans-serif;font-size:14px"> 36(2015):633-648.</span>" "<span style="font-family:AdvMyriad;font-size:9pt">The buffer region size required to reduce the force errors at the dynamical boundary below a preset threshold can be determined from the convergence of forces in the dynamical QM region as a function of buffer region size, carried out separately before the production run on a few relevant configurations (e.g., near the estimated extrema of a free energy profile). " </span><b><span style="font-size:9pt"><font face="arial, sans-serif">Here is my question: How can we get the force of the </font></span><span style="font-family:AdvMyriad;font-size:12px">dynamical QM region? I have put force put in the MOTION section (&MOTION&MD&PRINT&FORCE), and got the file of <font color="#0000ff">**-<a href="http://frc-1.xyz" target="_blank">frc-1.xyz</a>.</font> I also put force print in the QMMM FORCE_EVAL section (&FORCE_EVAL&PRINT&FORCE), and got the<font color="#0000ff"> ATOMIC FORCE in [a.u. ] </font>in the output file. </span></b></div><div><font face="AdvMyriad"><span style="font-size:12px"><b>How can I calculate the force of the dynamic QM region and how the test the convergence of it?</b></span></font></div><div><font face="AdvMyriad"><span style="font-size:12px"><b><br></b></span></font></div><div><font face="AdvMyriad"><span style="font-size:12px"><b>Thank you very much for your help.</b></span></font></div><div><font face="AdvMyriad"><span style="font-size:12px"><b><br></b></span></font></div><div><font face="AdvMyriad"><span style="font-size:12px"><b>Happy New year.</b></span></font></div><div><font face="AdvMyriad"><span style="font-size:12px"><b><br></b></span></font></div><div><font face="AdvMyriad"><span style="font-size:12px"><b>Wei</b></span></font></div> </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+uns...@googlegroups.com" target="_blank">cp2k+uns...@googlegroups.com</a>.<br> To post to this group, send email to <a href="mailto:cp...@googlegroups.com" target="_blank">cp...@googlegroups.com</a>.<br> Visit this group at <a href="https://groups.google.com/group/cp2k" target="_blank">https://groups.google.com/group/cp2k</a>.<br> For more options, visit <a href="https://groups.google.com/d/optout" target="_blank">https://groups.google.com/d/optout</a>.<br> </blockquote></div>