ERROR: Incorrect args for pair coefficients (src/USER-REAXC/pair_reaxc.cpp:309)

LAMMPS LAMMPS General Discussion
1

Hi,

I am trying to simulate a hierarchical carbon structure containing DMSO (C2H6OS) organic solvent using ReaxFF. My reactive forcefield file contains the parametric values for all the atoms types present in the structure (i.e., C, H, O, and S). However, my simulation gives following error;

“ERROR: Incorrect args for pair coefficients (src/USER-REAXC/pair_reaxc.cpp:309)”

Here is given below the input script. Kindly let me know how to fix it. Thanks

REAXff - MFI type ZTC

-------------------- Init Section ----------------------

units real
boundary p p p
atom_style charge
#bond_style harmonic
#angle_style harmonic
#dihedral_style harmonic
pair_style reax/c NULL

-------------------- Atom Definition Section ------------

read_data MFI_dmso.out
#change_box all x final 0 20 y final 0 20 z final 0 20
group C type 1 # C
group dmso type 2 3 4 5
group S type 2
group O_solvent type 3
group C_solvent type 4
group H_solvent type 5

#--------------------- Pair Coefficients ------------------------

pair_coeff * * ffield.reax.LIS C H O S

-------------------- Settings Section -------------------

neighbor 2 bin
neigh_modify every 10 delay 0 check no

timestep 0.1

fix 2 all qeq/reax 1 0.0 10.0 1e-4 reax/c

-------------------- Minimization -------------------

#fix 1 all nvt temp 300.0 300.0 500.0

fix 1 all npt temp 300.0 300.0 100.0 iso 10.0 10.0 2500.0

thermo 10
dump 1 all atom 1000 FAU-npt*.lammpstrj

run 100

thermo 100

thermo_style custom step time temp press pe ke etotal epair enthalpy vol density

min_style cg

minimize 1.0e-10 1e-10 10000 10000

write_data MFImin.data

2

Please note that atom types are not the same as elements and the pair_coeff command has to establish how one is mapped to the other. Yours obviously does not.

3

Dear Akohlmey,

Thank you for your response. I tried to keep element types and atom types same as given below;

read_data MFI_dmso.out
#change_box all x final 0 20 y final 0 20 z final 0 20
group C type 1 # C
group dmso type 2 3 4 5
group S type 2
group O type 3
group C type 4
group H type 5

#--------------------- Pair Coefficients ------------------------

pair_coeff * * ffield.reax.LIS ztc C S O C H

However, still getting the same error. Could you please elaborate it further. Thanks

4

What is ztc?

5

ztc is ‘zeolite templated carbon’ name of the structure which is made up of purely carbon (C) atoms.

6

So not an element. Then why is this there where the elements should be listed?

LAMMPS is a computer program and thus has no common sense or ability to reason. It blindly follows what it is programmed to do and that is described in the manual. Thus, unless you can provide convincing proof that the manual is incorrect, any errors of the obvious kind that you have been asking about recently can be resolved by carefully studying the manual. I suggest you take this under serious consideration before posting questions or else you will find that you are quickly exhausting the good will of the people that are responding to questions.

7

Thanks. Sure, I try to fix it reading manual again.