[lammps-users] AIREBO potential problems

Hello,

I’m using the airebo potential for graphite simulation. It seems that force calculated wrong. I can see this from NVE ensemble simulation, where “total energy” is not a constant. That is my example:
------input script----------------------------------------------------
units metal
boundary p p p

atom_style atomic

lattice custom 1.42 &
a1 3.0 0.0 0.0 a2 0.0 1.73205081 0.0 a3 0.0 0.0 4.78873239 &
basis 0.08333333 0.25 0.25 &
basis 0.41666667 0.25 0.25 &
basis 0.58333333 0.75 0.25 &
basis 0.91666667 0.75 0.25 &
basis 0.25000000 0.75 0.75 &
basis 0.41666667 0.25 0.75 &
basis 0.75000000 0.25 0.75 &
basis 0.91666667 0.75 0.75

region SimCell block 0 15 0 15 0 15 units lattice
create_box 1 SimCell

region Graphite block 0 15 0 15 0 15 units lattice
create_atoms 1 region Graphite units lattice

mass 1 12.011

pair_style airebo 3.0 1 0
pair_coeff * * CH.airebo C

velocity all create 300 13 dist gaussian
neighbor 1.0 bin
neigh_modify every 10 delay 50 check no

thermo 1
fix 1 all nve
run 10

You’d see the same thing if you used pair_style lj/cut. The AIREBO
potential has internal cutoffs. You may also be using too big
a timestep for AIREBO.

Steve