On Thu, 2012-02-23 at 13:35 -0700, Denny Frost wrote: > Dear all, > I am trying to equilibrate a solvent of pure ionic liquid. The system > keeps exploding (after 2-5 ns) and I am not sure why, though I believe > coulombic interactions are to blame. This is because the Coul-SR term > is negative, but the Coul. recip term is very positive throughout the > entire run (giving the entire system a positive potential energy). I > think this means that the short-range electrostatics are okay, but the > long range electrostatics (calculated with PME) are not. Does anybody > have any suggestions as to why this would happen? I have used the > exact same PME input parameters for another ionic liquid that works > just fine. They are listed below. > > > rcoulomb = 1.2 > fourierspacing = 0.12 > pme_order = 4 > ewald_rtol = 1e-5 >
Depends on the force field you are using. Perhaps it ist not validated for the ionic liquid you want to study. It is especially strange, that it takes so long for your system to blow up. Moreoever I would try to optimize the PME settings with the tools, g_tune_pme and g_pme_error, which give you performance and accuracy of the parameters, respectively. So perhaps with some more information I can provide more help. /Flo > > Thanks! > Denzil Frost > -- > gmx-users mailing list [email protected] > http://lists.gromacs.org/mailman/listinfo/gmx-users > Please search the archive at > http://www.gromacs.org/Support/Mailing_Lists/Search before posting! > Please don't post (un)subscribe requests to the list. Use the > www interface or send it to [email protected]. > Can't post? Read http://www.gromacs.org/Support/Mailing_Lists -- Florian Dommert Dipl. - Phys. Institute for Computational Physics University Stuttgart Pfaffenwaldring 27 70569 Stuttgart EMail: [email protected] Homepage: http://www.icp.uni-stuttgart.de/~icp/Florian_Dommert Tel.: +49 - (0)711 - 68563613 Fax.: +49 - (0)711 - 68563658
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