Electric_field

Dear lammps users,

I’m using lammps/reax/c for simulating decomposition of an organic compound under a constant electric field. From outputs (I mean dump.xyz and specie) I recognized that the electric field is worked but I’m not sure that it’s exactly correct or not. Please look into my input file and make recommends if it needs. This is my input file:

echo both

units real

dimension 3

boundary p p p

atom_style charge

read_data NBCom.data

#read_restart restart22

restart 500 restart11 restart22

pair_style reax/c NULL

pair_coeff * * ffield.reax.rdx C H O N

compute reax all pair reax/c

variable eb equal c_reax[1]

variable ea equal c_reax[2]

variable et equal c_reax[9]

variable ew equal c_reax[11]

variable efi equal c_reax[13]

variable eqeq equal c_reax[14]

#define a region for efield

region elecf block 0.0 100.0 0.0 100.0 0.0 100.0 units box

group elf region elecf

neighbor 2 bin

neigh_modify every 10 delay 0 check no

velocity all create 300 235485 mom yes rot yes

fix 1 all nvt temp 300 300 25 ###########timestep*100=25

fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c

fix 3 all reax/c/species 1 50 250 species.txt

fix 4 elf efield 2.0 0.0 0.0 region elecf

fix_modify 4 energy yes

thermo_style custom step atoms temp press vol etotal ke pe v_eb v_ea v_et v_ew v_efi v_eqeq

thermo 250

timestep 0.25

dump 1 all atom 30 dump.reax.rdx

dump 2 all xyz 30 dumpnvt.xyz

run 30000

Thanks in advance

Mohammad Ebrahim Izadi

Dear lammps users,

I’m using lammps/reax/c for simulating decomposition of an organic
compound under a constant electric field. From outputs (I mean dump.xyz
and specie) I recognized that the electric field is worked but I’m not sure
that it’s exactly correct or not. Please look into my input file and make
recommends if it needs. This is my input file:

​you seem to be confusing the purpose of a mailing list. it is most
certainly not an input file approval or debugging/correction service​.
in other words, it is part of the job of a researcher to validate that a
chosen model is giving results at the expected level of accuracy and
usefulness.

please let me repeat what i have pointed out in an earlier e-mail response.
when you are using fix efield, you are not exactly applying an electric
field, you are adding a force to all charged atoms, that depends on the
product of the (partial) charge of each atom and a given force constant
with conversion factor.
this does not include the electric field in the charge equilibration (only
indirectly over response to the force generated by fix efield) and there is
no screening or other effects taken under consideration.

​axel.​