Graphene Impact

LAMMPS input script

### Created by Eric N. Hahn ###

### ericnhahn@gmail.com ###

### Diamond impact of single graphene sheet ###

### Version 0.3 ###

# === Setup the simulation ===

log log.Graphene_impact

echo screen

dimension 3

units metal

atom_style atomic

boundary p p p

region box block -210 210 -240 240 -5 200 units lattice

create_box 1 box

lattice custom 2.4595 a1 1 0 0 a2 0 1.73203 0 &

basis 0 0 0 &

basis 0.5 0.16666666666666666 0 &

basis 0.5 0.5 0 &

basis 0 0.6666666666666666 0

region graphene block -210 210 -240 240 0 0.1 units lattice

create_atoms 1 region graphene

mass * 12.011

# === Define Interatomic Potential ===

pair_style airebo/morse 3.0

pair_coeff * * CH.airebo-m C

compute 3 all pe/atom

compute 4 all stress/atom NULL virial #note, ignores thermal contribution to stress

# === Run the simulation for equilibration ===

velocity all create 300.0 12345 dist gaussian

fix npt all npt temp 298 298 .5 x 0.0 0.0 .5 y 0.0 0.0 .5

thermo 10

thermo_style custom step pe ke etotal temp lx ly lz press atoms

dump eve all custom 25 dump.graphene_impact.* id type x y z vx vy vz c_3 c_4[1] c_4[2] c_4[3]

timestep 0.001

fix bp all balance 250 1 shift z 10 1

thermo_style custom step temp ke pe press vol

run 50

group graphene region graphene

variable ymn equal ylo+4

variable ymx equal yhi-4

variable xmn equal xlo+4

variable xmx equal xhi-4

region middle block ${xmn} ${xmx} ${ymn} ${ymx} -5 5 units box

group middle region middle

group edge subtract graphene middle

unfix npt

lattice diamond 3.567

region mobile sphere 0 0 150 30 units box

create_atoms 1 region mobile

group impactor region mobile

change_box all boundary p p s

# === Run the simulation for impact ===

reset_timestep 0

velocity edge set NULL NULL 0 sum no units box

fix sheet edge setforce NULL NULL 0.0

velocity impactor set 0.0 0.0 -20.0 sum yes units box #20 A/ps = 2 km/s

fix nve all nve

timestep 0.002

run 20000

print "Job's done"

"CH.airebo-m" potential can be found in the "potentials" folder of recent LAMMPS installations.

Looking for more examples of impacts? See what happens when multiple graphene layers are added by clicking here.