[lammps-users] Issues Related with Neighbor bins

Dear LAMMPS users,

During the simulation of pouring particles in a box, I have faced a problem regarding neighbor bins. The error showed in the windows cmd is: “Cannot use neighbor bins - box size << cutoff”. One of the atoms has a diameter 1000 times larger than the smaller ones. I have included some portion of the code in the email. Any kind of help or suggestion is appreciated.

#2D powder pouring in the box

dimension 2

lattice hex 0.88

atom_style sphere #Spheres has per-particle diameter and mass
boundary f fm p
newton off #Two interacting atoms are on different processors and the resulting force information is not communicated.
comm_modify mode multi vel yes #Conserving properties to two ghost atoms

fix prop all property/atom mol ghost yes

region reg block 0 10000 0 5000 -0.5 0.5 units box
create_box 1 reg

create_atoms 1 single 600 2000 0

region substratefirst block 1 6000 1 1000 -0.5 0.5 units box
region substratesecond block 6001 8000 1 1000 -0.5 0.5 units box
region substratethird block 8001 9999 1 1000 -0.5 0.5 units box

region substrate union 3 substratefirst substratesecond substratethird

create_atoms 1 region substrate

group 1 id < 2
group 2 id > 2

set atom 1 diameter 1000

set atom 1 density/disc 500

velocity 1 set 25 0 0 units box

neighbor 0.2 multi
neigh_modify delay 0

Any kinds of suggestions related to this?