CNT simulations

Hello all,

A very basic question. I am trying to find out thermal conductivity(k) for CNT of length L, 2L,3L and 4L ( where n=m=5 and L=5 Angstorm). The result obtained for 4L is perfect but the simulations for the remaining 3 is not getting executed.

The error message after fixing NPT is showing as follows : "Too many atom sorting bins"

Saw from the common problem section in the LAMMPS website that this can be due to an immense simulation box that has blown up to a large size.

But my question is, how did 4L run perfectly then? The simulation box size in that case was the largest.

Will be very helpful if someone can help. Thanks a lot.

It is quite difficult to comment without seeing the full input.

It is likely, though, that the structures that failed have bad boundary conditions.


But my question is, how did 4L run perfectly then? The simulation box size in that case was the largest.

What was the simulation box size at the point in time one of the other simulations
failed, and how do you know what size it was?


Thanks for the reply Ray and Steve. Even I am a bit confused about why are they not running. I created the CNT in VMD and its has chiral indices (5,5) and length L =5Angstorm. So 4L was 20 Angstorm and it ran perfectly well. Can you please help? Thanks.

My input script after fixing NPT, NVT and NVE successfully was:

Thermal Conductivity of CNT comprising of 360 atoms

log log.thermal
read_restart equil.restart

pair_style airebo 3.0 1 1
pair_coeff * * CH.airebo C
group Carbon type 1

reset_timestep 0
timestep 0.001
variable t equal 150000
thermo $t

fix NVT all nvt temp 300.0 300.0 0.1

compute ke Carbon ke/atom
variable temperature atom c_ke/(1.5*8.617e-5)

fix thermal all thermal/conductivity 300 z 100
thermo_style custom step temp pe ke etotal press lx ly lz f_thermal
run 4000000

write_restart equil2.restart

fix TEP all ave/spatial 1 10000 10000 z lower 3 v_temperature file temp.cnt units box
run 100000

write_restart equil3.restart

It is still difficult to comment because no one knows what the structure looks like and what the boundary conditions are.

Have you checked the box sizes? visualized the system?