How to choose timestep, thermo and Tdump parameters for Lammps simulations

LAMMPS LAMMPS Beginners
1

Hello everyone
I’m trying to run lammps simulations on a material (Lepidolite). I run the system but with a large temperature flutuaction going up to 60000K for exemple when I should be at 300K. How can I influence these three parameters to get realistic temperatures at the end? I’ve tried several combinations but nothing
Thank you soo much

control.in (2.1 KB)
data.lj (12.4 KB)
units real
dimension 3
boundary p p p
box tilt large
neighbor 2.0 bin
neigh_modify page 500000 one 50000 delay 0 every 1 check yes
atom_style full
pair_style lj/cut/coul/long 15
bond_style harmonic
angle_style harmonic

read_data data.lj

kspace_style pppm 1.0e-4
run_style verlet
timestep 0.001

thermo_style custom step time temp atoms etotal evdwl ecoul pe
thermo 1000
velocity all create 300.0 12345 mom yes rot yes dist gaussian
dump 1 all xyz 1000 Lep_hydrated.xyz
dump_modify 1 element H O K Li Al Si O F
dump 2 all dcd 1000 Lep_hydrated.dcd

fix 1 all nvt temp 300.0 300.0 100
run 100000000

write_restart Lep_hydrated.save

2

If you get that high a kinetic energy, it is usually a sign of bad force field parameters or a bad geometry or a bad topology or unsuitable box dimensions. You can try running a minimization before the MD, but that is rarely helpful to resolve a bad initial system setup.

Please note, that this kind of problem is more an issue of general MD simulation knowledge than specific to LAMMPS and you will more likely get meaningful assistance in these matters from someone local like an adviser, tutor, or experienced coworker.

3

Many thanks