Coulomb Interaction in LIGGGHTS-PUBLIC 3.4.1

Hello all,

I am new in LIGGGHTS so would need some help:

As part of my degree final project (related to modeling of electro-filters) I am trying to simulate the interaction between charged particles with/without an external electric field.
I have been researching the manuals, the forum, etc, but I could not find a solution to my problem:

I do not know how to add coulomb interaction between particles. I found on this forum that -in previous versions- this could work:

atom_style hybrid granular charge
…..
pair_style hybrid/overlay gran/hertz/history coul/cut ${rcut}
pair_coeff * * gran/hertz/history
pair_coeff * * coul/cut ${rcut}

But in LIGGGHTS-PUBLIC 3.4.1 that lines do not work at all. I could not find anything related to coulomb interaction in the manuals.

I do manage to insert atoms with the “create_atoms” command, to add charge with “set” and to add “efield”. However, I would like to insert particles by using “fix ins ID-group insert/pack” because it enables to set speed to particles . Also, Is it possible to add charge to particles using “fix ins ID-group insert/pack”. I attach below the input I would like to use.

I do not need other kind of interactions between particles/atoms, just electrostatic repulsion.

I was wondering if anybody could help me somehow. I will very pleased with any answer --including this kind of simulations in my project would be a plus and I have no much time!

Thanks in advance,

Sergio

Input (very basic!):

atom_style granular
atom_modify map array
boundary p p f
newton off
#echo both # output: none/screen/log/both

communicate single vel yes
units si

# Simulation box
region reg block -0.01 0.01 -0.01 0.01 0. 0.1 units box
create_box 1 reg

neighbor 0.002 bin
neigh_modify delay 0

#Material properties required for new pair styles
fix m1 all property/global youngsModulus peratomtype 5.e6
fix m2 all property/global poissonsRatio peratomtype 0.45
fix m3 all property/global coefficientRestitution peratomtypepair 1 0.3
fix m4 all property/global coefficientFriction peratomtypepair 1 0.5

#New pair style
pair_style gran model hertz tangential history #Hertzian without cohesion
pair_coeff * *

timestep 0.00005

# Applied fields
#fix gravi all gravity 9.81 vector 0.0 0.0 -1.0
#fix elecf all efield 1.0 0.0 0.0 # Does not work without defining charge

#distributions for insertion
fix pts1 all particletemplate/sphere 1 atom_type 1 density constant 7500 radius constant 5e-4
fix pdd1 all particledistribution/discrete 13487 1 pts1 0.3

#parameters
variable fraction equal 1e-3 #0.0 - 1

#region and insertion
group nve_group region reg
#particle insertion
fix ins nve_group insert/pack seed 115337 distributiontemplate pdd1 &
insert_every 500 overlapcheck yes all_in yes vel gaussian 0. 0. -0.1 0.05 0.05 0.01 &
region reg volumefraction_region ${fraction} ntry_mc 10000

#apply nve integration to all particles that are inserted as single particles
fix integr nve_group nve#/sphere

compute 1 all ke #erotate/sphere
thermo_style custom step atoms ke c_1 vol time
thermo 200
#thermo_modify
#compute_modify thermo_temp dynamic yes

run 1
dump dmp all custom 350 post/dump*.granular id type type x y z ix iy iz vx vy vz fx fy fz radius
#unfix ins
run 50000