[lammps-users] about AIREBO

Hi steve,

Thanks a lot for your letter.
These results don't sound reasonable since it is supposed that there is the formation of the carbon nanotube via the interaction between two graphene nanoribbons(reference: NANO
LETTERS 2007 Vol. 7, No.11,3349-3354).I didn't observe this phenomenon. Contrary, I observed the rupture. Since there are some broken bonds in the structure after running 40ps, I think there should be some fluctuations in the total energy.But, the result isn't like that. I set the same simulation system as those in the reference. Now I really puzzle at these results. Why does the structure of two layers of graphene nanoribbons become rupturable after running about 40 ps, where the total energy has no changes? why isn't there the formation of the CNT which is observed in the reference? Is there anything I have missed? Your any suggestions would be greatly appreciated.
The input file is as follows and log file ant the configuration are attached.



# bilayer graphene nanoribbons NVT ensemble simulation
log log.graphene1600-15
units metal
atom_style atomic
boundary p p p
read_data data.graphene1600-2
velocity all create 300.00 4928459 dist gaussian
pair_style airebo 3.0 1 1
pair_coeff * * /home/lanhe/CH.airebo C H
neighbor 0.3 bin
neigh_modify every 1 delay 0 check yes
minimize 1.0e-6 0.00001 1000 10000
fix 1 all nve
fix 2 all temp/rescale 3 300.0 300.0 10.0 1.0
dump 1 all custom 10000 dump.graphene1600-15 tag type x y z
timestep 0.0005
thermo 200
run 200000

log.graphene1600-15 (41.5 KB)

55ps-tilted view.bmp (990 KB)

The overall energy might not change much b/c the rupture
is accomodated somewhere else. If you think there is
a problem with the potential, I'd talk to Ase Henry (ase at mit.edu)
who developed it for LAMMPS.