[gmx-users] energy conservation

[Gavin Melaugh]

Hi all

I have run a very long NVT simulation >500ns of one molecule (220 atoms)
to try to assess the fluctuations in a particular event. When I analyse
the energies it seems that the conserved quantity drifts significantly.
Why would this be? Has it got to do with the thermostat I am using?
Please find below  the mdp file.


title       = Pull test
cpp         =
include     =
define      =
integrator  = md
nsteps      = 300000000
dt          = 0.001
nstxout     = 150000
nstvout     = 150000
nstlog      = 150000
nstenergy   = 15000
nstfout     = 150000
pbc         = no
nstlist     = 0
ns_type     = simple
vdwtype     = cut-off
rlist       = 0
rvdw_switch = 0
rvdw        = 0
coulombtype = cut-off
rcoulomb    = 0
tcoupl      = nose-hoover
tc_grps     = system
tau_t       = 0.1
ref_t       = 400
gen_vel     = no
gen_temp    =
constraints = none
comm_mode   = angular

Cheers

Gavin