GROMACS version: 2020

GROMACS modification: No

Hi guys,

Recent I ran several NVE simulations using different time steps (dt). And I found that when using extremely small time steps (like 0.1 fs), the total energy cannot conserve, however the larger time steps (like 0.5fs or 1fs) can generate a total energy that conserve at the beginning of the simulation. Here is my mdp options, which is very simple, is there anything wrong with my simulation setup?

Thanks!

total energy:

mdp options:

title = Define here

cpp = /lib/cpp

constraints = h-bonds

constraint-algorithm = LINCS

integrator = md

dt = 0.0001

nsteps = 100000

nstenergy = 10

nstxout = 10

nstvout = 10

nstfout = 10

nstlog = 10

nstxtcout = 0

cutoff-scheme = Verlet

nstlist = 10

coulombtype = PME

rvdw = 1.2

rlist = 1.2

rcoulomb = 1.2

fourierspacing = 0.1

pme_order = 4

ewald_rtol = 1e-5

Tcoupl = no

Pcoupl = no

gen_vel = no

gen_temp = 300

gen_seed = -1