I have updated my code a bit but for some reason this code of 1 Reaxff force field, 1 .eam file and lj potential to connect them:
# LAMMPS input script for simulation with Au wall and EMI-BF4
units real # Use real units
atom_style full # Atom style for ReaxFF, requires charges
boundary p p p # Periodic boundary conditions in all directions
#pair_style hybrid lj/charmm/coul/charmm eam reax/c
pair_style hybrid reax/c lj/charmm/coul/charmm 8 10 14 16 eam/alloy # should be 8 10 100 110
read_data /home/ay342/Senior_Design/eq_SYST_1000.dat # Reading data file with Au wall and EMI-BF4 molecule
# Gold (Au) interactions with other types - placeholder values
pair_coeff 1 6 lj/charmm/coul/charmm 0.100 2.50 # N-Au
pair_coeff 2 6 lj/charmm/coul/charmm 0.120 2.55 # C-Au
pair_coeff 3 6 lj/charmm/coul/charmm 0.050 2.45 # H-Au
pair_coeff 4 6 lj/charmm/coul/charmm 0.110 2.60 # B-Au
pair_coeff 5 6 lj/charmm/coul/charmm 0.090 2.50 # F-Au
# Define ReaxFF potential
pair_coeff * * ffield_IL.txt N C H B F # Atom types for EMI-BF4
# Embedded Atom Method
pair_coeff * * eam/alloy /home/ay342/Au-Au/Au_GLJ10_3.eam.alloy NULL NULL NULL NULL NULL Au
# Group definitions
group Au_wall type 1 # type 1 is for Au
group EMI_BF4 type 2 # type 2 is for EMI-BF4
however I continue to get an issue with my pair_style command, getting the error
ERROR: Illegal pair_style command (src/REAXFF/pair_reaxff.cpp:187)
Last command: pair_style hybrid reax/c lj/charmm/coul/charmm 8 10 14 16 eam/alloy # should be 8 10 100 110
Your pair style command is incorrect. The ReaxFF pair style has a mandatory argument which seems to be missing here.
Ah I forgot to list NULL after reax/c. Another question if you have a moment. There seems to also be an issue with the line pair_coeff * * ffield_IL.txt N C H B F stating that it has an invalid hybrid style. This pair_coeff alone works when not using hybrid with the wall. Are there any changes i should make to my code for it to fit hybrid
Yes, please check the documentation.
P.S.: the name of the pair style is reaxff for several years already. The reax/c is deprecated and will be removed soon.
Thank you, after looking through the documentation, with this code:
# LAMMPS input script for simulation with Au wall and EMI-BF4
units real # Use real units
atom_style full # Atom style for ReaxFF, requires charges
boundary p p p # Periodic boundary conditions in all directions
pair_style hybrid reaxff NULL lj/charmm/coul/charmm 8 10 14 16 eam/alloy # should be 8 10 100 110
read_data /home/ay342/Senior_Design/eq_SYST_1000.dat # Reading data file with Au wall and EMI-BF4 molecule
# Define ReaxFF potential
pair_coeff * * ffield_IL.txt C H N B F # Atom types for EMI-BF4
# Gold (Au) interactions with other types - placeholder values
pair_coeff 2 1 lj/charmm/coul/charmm 0.120 2.55 # C-Au
pair_coeff 3 1 lj/charmm/coul/charmm 0.050 2.45 # H-Au
pair_coeff 4 1 lj/charmm/coul/charmm 0.100 2.50 # N-Au
pair_coeff 5 1 lj/charmm/coul/charmm 0.110 2.60 # B-Au
pair_coeff 6 1 lj/charmm/coul/charmm 0.090 2.50 # F-Au
# Embedded Atom Method
pair_coeff * * eam/alloy /home/ay342/Au-Au/Au_GLJ10_3.eam.alloy Au NULL NULL NULL NULL NULL
I continue to get this error:
ERROR: Pair coeff for hybrid has invalid style: ffield_IL.txt (src/pair_hybrid.cpp:500)
Last command: pair_coeff * * ffield_IL.txt C H N B F # Atom types for EMI-BF4
Apologies, but I cannot see the error as it appears that I am writing it in the same format as the document
You are using pair style reaxff as a sub-style of pair style hybrid. That requires changes to the pair_coeff commands so they can be mapped to the various sub-styles. You have augmented the pair_coeff commands for the other sub-styles. Why not for pair style reaxff?
I initially changed the pair_coeff command to be pair_coeff * * reaxff ffield_IL.txt C H N B F # Atom types for EMI-BF4 but I also got shown an error stating that it was Incorrect args for pair coefficients instead. Aside from this I was unsure of any other changes to make to the code.
The error message is correct, but that is a different error. You have apparently 6 atom types, but there are only 5 element to type mappings. Again, this is all documented. You just need to read the documentation with significantly more care and specifically the parts related to hybrid styles.
On a hunch, I checked the archives and have to remind you of this post by @srtee. It is rarely a good idea to use a hybrid pair style with ReaxFF, but this one seems particularly bad. A large part of the interactions of polar molecules with metal surfaces is the polarization of the metal (for an ideally polarizable metal, the induced charges are of the same magnitude but opposite sign as the original charges). With an ionic liquid, this is particularly large, yet by using you setup, you only have a mechanical coupling (i.e. no polarization at all) and not even the embedding term of the copper is correct since the contribution from the molecules at the surface are not considered.
In summary, you need more help than a forum can provide and at a much more fundamental level. Both in how to use a software correctly and follow its documentation and in how to set up complex simulations and in understanding the models that you are using within the simulation.
The hybrid pair style in LAMMPS can be a very powerful and useful tool, but like many other powerful tools, it needs to be used with care and consideration.