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

[gozde ergin]

---------- 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:


































*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