Lammps input

disboateng · February 11, 2022, 6:10pm

Im running copyrolysis simulation for Cellulose and polyopropylene at the end when when i view it in ovito, you would see the molecules are not well disintegrated even at high temperatures of 5000K.
this is my input file
is there anything wrong with it
#REAX potential for CHO system

…

units real
dimension 3
boundary p p p
processors * * *
atom_style charge
read_data structure.txt
pair_style reax/c control.txt
pair_coeff * * potential.txt C H O
neighbor 2 bin
neigh_modify every 1 delay 1 check yes

#minimization
fix 1 all qeq/reax 1 0.0 10.0 1e-6 reax/c
dump 1 all custom 100 dump1-minimization.file mass type xs ys zs fx fy fz vx vy vz
min_style cg
minimize 1e-8 1e-8 100000 100000
write_restart restart-minimization.file
write_data data-minimization.file
unfix 1

#heating to room temp for 100ps
reset_timestep 0
velocity all create 300 34523 dist gaussian
fix 1 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 2 all nve
fix 3 all temp/berendsen 300.0 300.0 1
fix 4 all reaxff/bonds 100 bonds-300K.reaxff
fix 5 all reaxff/species 10 10 100 species-300K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.1
dump 2 all custom 100 dump2-heating.file mass type xs ys zs fx fy fz vx vy vz
run 500
run 500
run 500
run 500
run 500
run 500
run 500
run 500
write_restart restart-heating.file
write_data data-heating.file
unfix 1
unfix 2
unfix 3
unfix 4
unfix 5

#nvt at 500 K for 100 fs
reset_timestep 0
velocity all create 500 34523 dist gaussian
fix 1 all nvt temp 500 500 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-500K.reaxff
fix 4 all reaxff/species 10 10 100 species-500K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 3 all custom 100 dump3-500K.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 2500
run 2500
write_restart restart-500K.file
write_data data-500K.file
unfix 1
unfix 2
unfix 3
unfix 4

#nvt at 1000 K for 100 fs
reset_timestep 0
velocity all create 1000 34523 dist gaussian
fix 1 all nvt temp 1000 1000 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-1000K.reaxff
fix 4 all reaxff/species 10 10 100 species-1000K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 4 all custom 100 dump4-1000.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 2500
run 2500
write_restart restart-1000K.file
write_data data-1000K.file
unfix 1
unfix 2
unfix 3
unfix 4

#nvt @ 1500K for 100fsreset_timestep 0
velocity all create 1500 34523 dist gaussian
fix 1 all nvt temp 1500 1500 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-1500K.reaxff
fix 4 all reaxff/species 10 10 100 species-1500K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 5 all custom 100 dump5-1500K.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 2500
run 2500
write_restart restart-1500K.file
write_data data-1500K.file
unfix 1
unfix 2
unfix 3
unfix 4

#nvt at 2000 K for 100 fs
reset_timestep 0
velocity all create 2000 34523 dist gaussian
fix 1 all nvt temp 2000 2000 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-2000K.reaxff
fix 4 all reaxff/species 10 10 100 species-2000K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 6 all custom 100 dump6-2000K.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 2500
run 2500
write_restart restart-2000.file
write_data data-2000.file
unfix 1
unfix 2
unfix 3
unfix 4#nvt at 2500 K for 100 fs
reset_timestep 0
velocity all create 2500 34523 dist gaussian
fix 1 all nvt temp 2500 2500 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-2500K.reaxff
fix 4 all reaxff/species 10 10 100 species-2500K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 7 all custom 100 dump7-2500K.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 2500
run 2500
write_restart restart-2500.file
write_data data-2500.file
unfix 1
unfix 2
unfix 3
unfix 4

#nvt at 3000 K for 100 fs
reset_timestep 0
velocity all create 3000 34523 dist gaussian
fix 1 all nvt temp 3000 3000 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-3000K.reaxff
fix 4 all reaxff/species 10 10 100 species-3000K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 8 all custom 100 dump8-3000K.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 2500
run 2500
write_restart restart-3000.file
write_data data-3000.file
unfix 1
unfix 2
unfix 3
unfix 4

#nvt at 3500 K for 100 fs
reset_timestep 0
velocity all create 3500 34523 dist gaussian
fix 1 all nvt temp 3500 3500 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-3500K.reaxff
fix 4 all reaxff/species 10 10 100 species-3500K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 9 all custom 100 dump9-3500K.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 2500
run 2500
write_restart restart-3500.file
write_data data-3500.file
unfix 1
unfix 2
unfix 3#nvt at 4000 K for 100 fs
reset_timestep 0
velocity all create 4000 34523 dist gaussian
fix 1 all nvt temp 4000 4000 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-4000K.reaxff
fix 4 all reaxff/species 10 10 100 species-4000K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 10 all custom 100 dump10-4000K.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 1250
run 1250
run 1250
run 1250
run 2500
write_restart restart-4000.file
write_data data-4000.file
unfix 1
unfix 2
unfix 3
unfix 4

#nvt at 4500 K for 100 fs
reset_timestep 0
velocity all create 4500 34523 dist gaussian
fix 1 all nvt temp 4500 4500 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-4500K.reaxff
fix 4 all reaxff/species 10 10 100 species-4500K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 11 all custom 100 dump11-4500K.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 2500
run 2500
run 2500
write_restart restart-4500.file
write_data data-4500.file
unfix 1
unfix 2
unfix 3
unfix 4

#nvt at 5000 K for 100 fs
reset_timestep 0
velocity all create 5000 34523 dist gaussian
fix 1 all nvt temp 5000 5000 1
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c
fix 3 all reaxff/bonds 100 bonds-5000K.reaxff
fix 4 all reaxff/species 10 10 100 species-5000K.out
thermo_style custom step temp epair emol etotal press density vol bonds pe ke evdwl
thermo 100
timestep 0.01
dump 12 all custom 100 dump12-5000K.file mass type xs ys zs fx fy fz vx vy vz
run 2500
run 2500
run 2500
run 2500
write_restart restart-5000k.file
unfix 1
unfix 2
unfix 3
unfix 4

akohlmey · February 11, 2022, 10:41pm

You are not likely to find somebody that will look through your input files, review them, and give you notes.
That is the job of an adviser or tutor. A forum or mailing list cannot replace that.
In general when learning a new skill or method, you need to start with something (much!) simpler and slowly build your skills and confidence. Starting with ReaxFF simulations (which is a force field requiring advance skills and a good understanding of its properties, capabilities and limitations) is not a good idea.