[lammps-users] Why atoms "not" moving?

Hi ,

i am making the following simulation,and when i am trying to visualize the trajectories i see that the atoms almost stay still (very small movement). Is it a visualization error or a lammps' error the one i am doing? I have minimized my system before the main simulation.

dimension 3
boundary p p p
units real
atom_style molecular
neighbor 0.3 bin
neigh_modify delay 5
read_restart co2min-Rav-swnt.restart
# Type 2: Carbon atoms
# Type 1: CO2 atoms
group CO2 type 1
group tubes type 2
pair_style lj/cut 10.0
pair_coeff 1 1 0.468781 3.454 10.0 #CO2-CO2 epsilon(kcal/mol) sigma(A)
pair_coeff 2 2 0.0 3.0 0.0 #C*-C*
pair_coeff 1 2 0.557 3.40 10.0 # CO2-C*
# the tubes are frozen
#fix 1 tubes rigid single
#fix 2 tubes setforce 0.0 0.0 0.0
fix 6 CO2 npt temp 300 300 100 iso 1.0 1.0 1000.0

#equilibrate
thermo 100
thermo_style custom etotal ke temp pe press vol
thermo_modify line multi
timestep 1.0
dump 1 all atom 1000 Rav-bun-swnt.lammpstrj
dump_modify 1 image yes

timestep 0.5
run 200000
thermo 100
log produc.log
thermo_style custom etotal ke temp pe press vol
thermo_modify line multi
run 2000000
write_restart Rav-swnt.restart

Dear Dimitrios,

Which atoms are you concerned about Tube or CO2?
Are your CO2 molecules far apart from each other? If that is the case, the feel no forces from each other as you minimized the system (so very minimal forces). You have not assigned any velocities to the atoms (so no initial velocities). This could be the reason you are not seeing anything realistic. Assign velocities to the CO2 atoms and see what happens.

No they are not far apart from them. I have run the simulation without the tubes and it works fine. Then i added the tubes and i have these results. But i had minimized the system back then without the tubes too. Wouldn't be wrong to run the simulations without minimizing my system ?