low-gradient correction for reaxff/c (UNCLASSIFIED)

Classification: UNCLASSIFIED
Caveats: NONE


I am trying to use the keyword lgvdw to turn on the low gradient correction of the ReaxFF/C for long range London Dispersion. When I do this I get the following output error:

"Warning: inconsistent vdWaals-parameters
Force field parameters for element SI
indicate shielding without inner wall, but earlier
atoms indicate different vdWaals-method.
This may cause division-by-zero errors.
Keeping vdWaals-setting for earlier atoms."

Which is repeated several times where at times the element SI is replaced by element X

The input structure in the data file that I use does not even use the element SI or X.

I am using the ffield.reax.lg file that comes with LAMMPS.

Here is my input file:

# set equilibrium conditions

variable p equal 1.0
variable pdamp equal 500
variable T equal 298
variable Tdamp equal 100
variable volume equal vol # the current volume (don't change)
variable totalEnergy equal etotal # total energy (don't change)

# output setting for averaging
variable avefreq equal 1

units real
atom_style full

# read restart or data file
read_data data.s0
#read_restart s0a.rst

pair_style reax/c NULL lgvdw yes
pair_coeff * * ffield.reax.lg 2 1 1 1 3 3 1 1

# optionally compute reax energies
# compute reax all pair reax/c

neighbor 2.5 bin
neigh_modify every 10 delay 0 check yes

# charge equilbration
fix 2 all qeq/reax 1 0.0 10.0 1.0e-6 reax/c

# print output to stdout
thermo 100

# write output to file
dump 1 all atom 10000 s0.lammpstrj
dump 2 all xtc 1000 s0.xtc
timestep 0.1

fix 3 all npt temp $T $T $Tdamp iso $p $p $pdamp

# time averages
fix 4 all ave/time 1 \{avefreq\} {avefreq} c_thermo_press v_volume v_totalEnergy c_thermo_temp file s0.ave title1 "State 0: Step Pressure Volume Energy Temp"

# toggle writing between two restart files
# safe since timeout could occur while writing one

restart 100 s0a.rst s0b.rst

run 100000

where the data file looks like this:

LAMMPS data file

5416 atoms

8 atom types

-6.5102778819816720e-01 3.7673027788192748e+01 xlo xhi
-6.5102778819816720e-01 3.7673027788192748e+01 ylo yhi
-6.5102778819816720e-01 3.7673027788192748e+01 zlo zhi


1 1.00797
2 12.0112
3 12.0112
4 12.0112
5 15.9994
6 15.9994
7 12.0112
8 12.0112


534 1 7 -1.0600000000000000e-01 3.1529072596819039e+00 3.7346248194626006e+00 2.4466532725122034e+00 2 0 0

Any suggestions for what I can be doing incorrectly?


Classification: UNCLASSIFIED
Caveats: NONE