I like extreme conditions... Seriously. OPLS water, as well as other popular MM waters, are parametrized for liquid state. I think you need to decrease model's dipole moment and you have to work with an integration time-step to ensure adequate energy conservation at ca. 600K.
I believe there should be exotic water models that were trained to reproduce the phase diagram to certain extent. Vitaly On Fri, Feb 14, 2014 at 7:58 PM, CipPruteanu <c.prute...@ed.ac.uk> wrote: > Hi everyone! > > I am trying to run a simulation of methane-water mixtures under extreme > conditions, that is around 25 kbars and 600K (and maybe higher in both > pressure and temperature). > > I am currently using OPLS for methane with TIP3P for water. The way I > proceed is as follows: > > -generate a box of methane and water having my desired concentration > -do an energy minimization for 100ps > -do a NVT equilibration at my desired temperature for 100ps > -do a NPT equilibration at my desired pressure and temperature for 100ps > > -run the simulation (NPT) for as long as I desire (1-10 ns for the moment) > > The simulations I ran on the individual components get reasonably good > results for them under these conditions. However, once I put them together, > the mixture doesn't behave as expected (by recent experimental findings). > > Is this approach ok or is there something fundamentally flawed about it ? I > know the fact that the forcefields are not meant to be used at these high > pressures/temperatures, but apart from that, is there anything I could > improve? > > -- > View this message in context: > http://gromacs.5086.x6.nabble.com/Simulations-in-extreme-conditions-tp5014553.html > Sent from the GROMACS Users Forum mailing list archive at Nabble.com. > -- > Gromacs Users mailing list > > * Please search the archive at > http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! > > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists > > * For (un)subscribe requests visit > https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a > mail to gmx-users-requ...@gromacs.org. -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.
