[gmx-users] Fwd: NVT to NVE ensemble, energy drifting problem

[Vitaly V. Chaban]

Decrease the time-step.




On Tue, Nov 3, 2015 at 3:00 PM, gozde ergin <gozdeeergin at gmail.com> wrote:

> ---------- Forwarded message ----------
> From: gozde ergin <gozdeeergin at gmail.com>
> Date: Tue, Nov 3, 2015 at 5:39 PM
> Subject: NVT to NVE ensemble, energy drifting problem
> To: mailing list Gromacs <gromacs.org_gmx-users at maillist.sys.kth.se>
>
>
> Dear Gromacs user,
>
> I did some simulation in NVT ensemble now I need to switch and do some more
> simulations in NVE ensemble.
> What properties do I need to change in .mdp file to get a good energy
> conversion?
> I used the same properties like NVT without temperature coupling but my
> potential and kinetic energy drifted a lot.
> What should I do prevent this drifting?
>
> Here is my nvt.mdp:
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> *integrator               = md     dt                       =
> 0.002nsteps                   = 10000000   ; 20 nsnstxout
> = 10000nstvout                  = 10000nstlog                   =
> 10000nstenergy                = 10000continuation         = no
> constraint_algorithm = lincs  constraints          = all-bonds
> lincs_iter           = 1        lincs_order          = 4        ns_type
> = grid             nstlist     = 5                rlist       =
> 1.2               rcoulomb    = 1.2              rvdw        =
> 1.2              coulombtype     = PME        pme_order       =
> 4             fourierspacing  = 0.16         tcoupl                   =
> nose-hoovertc-grps                  = Systemtau_t                    =
> 1.0ref_t                    = 300Pcoupl                   = Nopbc     =
> xyz                DispCorr    = EnerPres          gen_vel     =
> yes            gen_temp    = 310               gen_seed    =
> -1               nstcomm         = 10comm-mode       =
> Linearcomm-grps       = System *
> For nve, I just make the temperature coupling off and used the same
> properties however as I mentioned my energy could not converged in 20 ns.
>
> Thanks in advance
> --
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