[lammps-users] lammps with AIREBO


I would like to run a simulation at high T (8000 K) using the AIREBO
potential. The goal is to "melt" a diamond surface. I tried using the
fix langevin command, but I keep losing atoms. Does anyone have any
ideas how I can make this work?


Here is the input file:

boundary p p f

atom_style molecular
units metal
neighbor 2.0 bin
neigh_modify delay 0 every 1 check yes

read_data timelang.dat

pair_style airebo 3.0
pair_coeff * * CH2.airebo C C C H

group melt type 1
group top type 3 4
group freeze type 2
group nonmobile type 2 3 4

fix 1 melt langevin 0 8000 30 1994
fix 2 melt nve/limit 0.001

compute Tmelt melt temp

timestep 0.0001
thermo_style custom step c_Tmelt temp ke pe etotal
thermo 1000

dump coords all xyz 1000 timelang.dump
dump vels all custom 1000 timelang.vel tag vx vy vz

minimize 0 1.0e-9 1000 10000
run 300000

With boundary f you will lose atoms if they move across that
boundary. Try boundary s instead. Or figure out why the atoms
are moving across that boundary if they shouldn't be.