<div dir="ltr">Hi, I am trying to reproduce a tutorial that uses Gaussian with CP2K, and I have problems reproducing the results originally achieved. The tutorial describes a fairly simple Diels-Alder reaction using PM3 semiempirical. This is an old GROMACS tutorial that uses Gaussian98: <a href="http://wwwuser.gwdg.de/%7Eggroenh/EMBO2004/html/qmvacuum.html#top">http://wwwuser.gwdg.de/%7Eggroenh/EMBO2004/html/qmvacuum.html#top</a> I was able to reproduce the reactant, transition state and product energies described in the tutorial using Gaussian09. However, when I attempted to reproduce the results with CP2K, I do not obtain the same energy profile. I am asking for advice on how to fix this problem and obtain reproducible results in CP2K. I have documented the protocol to run these simple calculations here : https://github.com/bioexcel/cp2K_qmmm_tutorials_for_biological_simulations/tree/master/GMX_DAA These are the results I obtained so far. <table cellspacing="0" cellpadding="0" style="border-collapse: collapse"> <tbody> <tr> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> Energy / kJ mol-1 </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> Reactants </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> Transition States </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> Product </td> </tr> <tr> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> GMX Tutorial (Gaussian98) </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> 0.00 </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> 202.17 </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> -34.13 </td> </tr> <tr> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> Gaussian09 </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> 0.00 </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> 200.06 </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> -36.37 </td> </tr> <tr> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> CP2K </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> 0.00 </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> 152.65 </td> <td valign="top" style="border-style: solid; border-width: 1.0px 1.0px 1.0px 1.0px; border-color: #9a9a9a #9a9a9a #9a9a9a #9a9a9a; padding: 1.0px 5.0px 1.0px 5.0px"> -175.81 </td> </tr> </tbody> </table> I tried to fine-tune the parameters of the input file but I cannot find the reason behind these different energy profiles. Here it is a list of the different attempts to solve this problem I tried: <ul> <li style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: "Helvetica Neue";">The optimiser has a very significant effect on the structure.</li> <ul style="list-style-type: disc"> <li style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: "Helvetica Neue";">CG gets a similar structure than Gaussian.</li> <li style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: "Helvetica Neue";">BFGS leads to the structure after SO2 expulsion. This method cannot be used with the DIMER method. </li> </ul> <li style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: "Helvetica Neue";">SCF convergence: Using MAX_SCF 2000 is useful to converge the SCF in these simulations.</li> <li style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: "Helvetica Neue";">GRID CUTOFF convergence doesn't affect the accuracy of these small systems.</li></ul> Please find attached input and output files for these files. Also you can find the protocol used in this GitHub environment: https://github.com/bioexcel/cp2K_qmmm_tutorials_for_biological_simulations/tree/master/GMX_DAA Thank you very much in advance, Salomé Llabrés, PhD Applications developer in Data science EPCC University of Edinburgh, UK</div>