Illegal pair_style reaxff ERROR

LAMMPS LAMMPS Beginners
1

Dear Lammps Users,

I am trying to simulate C1N1 monolayer using reaxff forcefield in Lammps. My Lammps version is :LAMMPS/29Aug2024-foss-2023b-kokkos on the HPC.

I checked if the package REAXFF is included in the installed Lammps using : lmp -h | grep reaxff
rann reaxff reaxff/kk reaxff/omp rebo
accelerate/cos acks2/reax acks2/reaxff acks2/reaxff/kk acks2/reax/kk
qeq/comb/omp qeq/dynamic qeq/fire qeq/point qeq/reaxff
qeq/reax qeq/reaxff/kk qeq/reax/kk qeq/reaxff/omp qeq/reax/omp
qeq/shielded qeq/slater qtb rattle reaxff/bonds
reaxff/bonds/kk reaxff/species reaxff/species/kk recenter
reaxff/atom reaxff/atom/kk reduce reduce/chunk reduce/region

I am consistently getting error :
ERROR: Illegal pair_style command (src/REAXFF/pair_reaxff.cpp:188)
Last command: pair_style reaxff

I installed lammps on my desktop (lammps-stable_29Aug2024_update2) and also manually installed the package REAXFF followed by make serial. Nevertheless i still get the same error on not recognizing the pair_style reaxff. I have attached the lammps input file for your consideration. Any suggestion will be very useful.

Thanks and Best Regards,
Deepak
c1n1_reaxff.in (407 Bytes)

2

It means that the syntax of your pair_style command does not follow the specifications, regardless of which version of LAMMPS you try it with. The best way forward is to study the corresponding manual entry.

3

Apart from the obvious syntax error that @hothello was mentioning, you also are using a ReaxFF combustion force field parameterized for studying the RDX explosive. I don’t think that parameter set is suitable for your objective.

4

Thanks a lot for the reply. I have checked the syntax on manual. The basic input section is

pair_style reaxff checkqeq yes
pair_coeff * * ffield.reax.rdx C N

I have validated it in details but i am not sure what the error is in the statement. In the forcefield file, the sequence is also in order of C and then N so i really cant figure out the error.

5

Hint: where is the control file? It’s all documented, so please do your work.

6

Thanks a lot @hothello

7

Thanks @akohlmey I will try to use different pair style.