Reaxff/species with 'delete' keyword

Greetings LAMMPS users

I want to use the fix reaxff/species command with the delete keyword. I can run the simulation just fine without the delete keyword, but once I include ‘delete’ I receive an error for an illegal fix reaxff/species command. I have utilized both the specieslist and masslimit methods for deletion, but I receive the same error with each. Has anyone come across this? I’ve scoured the forums and LAMMPS manual for a potential solution, but I am unfortunately stuck. I don’t think I’ve entered the command wrong, I’ve copied and pasted the lammps code below.



units real
dimension 3
boundary p p p
atom_style full

reaxff potential information

pair_style reaxff lmp_control_lg checkqeq no
pair_coeff * * ffield.reax.chosfcln F C C

fix 1 all reaxff/species 1 100 100 species.out element F C C delete CF2.del specieslist 3 C F CF2

pyrolysis at 3000K 1 atm

fix 2 all npt temp 3000 3000 10000 aniso 1.0 1.0 1000
thermo_style custom step temp pe press vol density
thermo 10000
timestep 0.25 #fs
reset_timestep 0
dump MyData all xyz 10000
run 1000000
unfix 2
undump MyData
write_data 3000.dat

You should always report your LAMMPS version when reporting an issue. In this case, if you look at the stable version’s documentation here, there’s no delete keyword, whereas it exists in the latest release version.


This feature was added in Reaxff species 'delete' keyword by jrgissing · Pull Request #3298 · lammps/lammps · GitHub which is available in LAMMPS since version 3 August 2022.

Sorry I’m new to all of this, I will remember to report my LAMMPS version in the future when I have an issue. Thank you very much, I do not have the latest version, so that is obviously what went wrong. Take care.

Understood, thank you.

Hi Aaron,

In case you find it helpful, I have added one more feature to the ‘delete’ keyword, which allows you to enforce an upper limit on the rate of molecule deletions. Note that this feature is currently only available in the ‘develop’ branch.