Hi Alin and Matthias,<div><br /></div><div>Thanks for the quick reply, I didn't know that! If so, the 110/900 combination in the water.inp file should be correct then right? Still, in a lot of input files in the tests folder like for example cp2k/tests/Fist/regtest-4/H2O-1.inp (see attachment) the combination 55/450 is used. Can you explain why this is the case then?</div><div><br /></div><div>Kind regards,</div><div>Léon</div><br /><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Friday 12 January 2024 at 10:02:01 UTC+1 Krack Matthias 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 lang="en-CH" link="blue" vlink="purple" style="word-wrap:break-word"> <div> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">Dear Léon<u></u><u></u></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt"><u></u> <u></u></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">Note that LAMMPS uses a d<a href="https://docs.lammps.org/angle_harmonic.html" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://docs.lammps.org/angle_harmonic.html&source=gmail&ust=1705136600968000&usg=AOvVaw32JtUMzxYsuLEtm7RaruCZ">ifferent potential definition</a>. By contrast to CP2K, LAMMPS includes the prefactor ½ into the constant K.<u></u><u></u></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt"><u></u> <u></u></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">HTH<u></u><u></u></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt"><u></u> <u></u></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt">Matthias <u></u><u></u></span></p> <p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt"><u></u> <u></u></span></p> <div> <div></div></div></div></div><div lang="en-CH" link="blue" vlink="purple" style="word-wrap:break-word"><div><div><div> <div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0cm 0cm 0cm"> <p class="MsoNormal" style="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"><a href data-email-masked rel="nofollow">cp...@googlegroups.com</a> <<a href data-email-masked rel="nofollow">cp...@googlegroups.com</a>> on behalf of Léon Luntadila Lufungula <<a href data-email-masked rel="nofollow">Leon.luntad...@uantwerpen.be</a>><br> <b>Date: </b>Friday, 12 January 2024 at 09:53<br> <b>To: </b>cp2k <<a href data-email-masked rel="nofollow">cp...@googlegroups.com</a>><br> <b>Subject: </b>[CP2K:19726] Correct TIP3P parameters<u></u><u></u></span></p> </div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">Dear all,<u></u><u></u></span></p> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"><u></u> <u></u></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">Just a quick question about the parameters for the TIP3P forcefield. In the example files (see attached water.inp) of the </span><a href="https://www.cp2k.org/exercises:2019_uzh_acpc2:ex02" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://www.cp2k.org/exercises:2019_uzh_acpc2:ex02&source=gmail&ust=1705136600969000&usg=AOvVaw1BkwBnD4nLgw0RRIp_XbgQ"><span style="font-size:11.0pt">exercise</span></a><span style="font-size:11.0pt"> on molecular simulation of water the TIP3P model is used to simulate water. In the input file, I noticed that the force constant of the H-O-H bend and the H-O bond are 110 rad^-2kcalmol and 900 angstrom^-2kcalmol, respectively. However, when looking online for the parameters like on the </span><a href="https://docs.lammps.org/Howto_tip3p.html" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://docs.lammps.org/Howto_tip3p.html&source=gmail&ust=1705136600969000&usg=AOvVaw00tIMiobjqNYoMie9tN0BE"><span style="font-size:11.0pt">lammps documentation</span></a><span style="font-size:11.0pt">, I find that these values are actually half of what is defined in the input, i.e., 55 rad^-2kcalmol and 450 angstrom^-2kcalmol, respectively... Is this indeed an error in the input file or am I missing something here? Most water input files I see in the tests/Fist folder also contain the smaller values for the force constants.<u></u><u></u></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"><u></u> <u></u></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">Kind regards,<u></u><u></u></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">Léon<u></u><u></u></span></p> </div> </div></div></div></div><div lang="en-CH" link="blue" vlink="purple" style="word-wrap:break-word"><div><div><div><p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt">-- <br></span></p></div></div></div></div><div lang="en-CH" link="blue" vlink="purple" style="word-wrap:break-word"><div><div><div><p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"> 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 </span></p></div></div></div></div><div lang="en-CH" link="blue" vlink="purple" style="word-wrap:break-word"><div><div><div><p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"></span><a href data-email-masked rel="nofollow"><span style="font-size:11.0pt">cp2k+uns...@googlegroups.com</span></a><span style="font-size:11.0pt">.</span></p></div></div></div></div><div lang="en-CH" link="blue" vlink="purple" style="word-wrap:break-word"><div><div><div><p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"><br> To view this discussion on the web visit </span></p></div></div></div></div><div lang="en-CH" link="blue" vlink="purple" style="word-wrap:break-word"><div><div><div><p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:11.0pt"></span><a href="https://groups.google.com/d/msgid/cp2k/2bed3d68-2c9d-4ceb-8672-208cfe7d0fd8n%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://groups.google.com/d/msgid/cp2k/2bed3d68-2c9d-4ceb-8672-208cfe7d0fd8n%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1705136600969000&usg=AOvVaw3RW5KmeAacn-7SiCe6DVev"><span style="font-size:11.0pt">https://groups.google.com/d/msgid/cp2k/2bed3d68-2c9d-4ceb-8672-208cfe7d0fd8n%40googlegroups.com</span></a><span style="font-size:11.0pt">.<u></u><u></u></span></p> </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/06168420-2bcc-4588-bd81-05bfcf6ac9den%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/06168420-2bcc-4588-bd81-05bfcf6ac9den%40googlegroups.com</a>.<br />