Bulk simulation - Molecules are moving

Dear LAMMPS user,

I am having a weird problem using lammps. In the attached script files I was trying to simply run MD for a bulk CO2 system for test purposes.

Surprisingly, with no means molecules move!! The simulation performs fine but the generated trajectories are exactly similar to the initial configuration which means obviously the molecules are not moving! Thermodynamic properties of the system are also constant! Moreover I am not able to apply the NVT/NVE fix commands. Once I switch them on the simulation crashes with an “out of rang atom” error.

I have tried many different scenarios to fix the problem but considering I am very new with LAMMPS, I wonder if anybody could kindly assist me with this and let me know where the problem may come from.

Best regards,


data.initial1 (26.9 KB)

in.sicdc1 (1.89 KB)

If you don't use a fix nve (or nvt) command, atoms will not move.

If you do use them, and you get the error, then you are likely
doing bad dynamics. E.g. too big a timestep, too big of forces (bad
initial config), etc.