Dear colleagues,
I am currently using the August 2, 2023 version of LAMMPS. In my research on the gasification of coke with CO₂ under microwave (applied electric field), I attempted to simulate the effect of microwaves by applying an electric field, as referenced in literature. However, I encountered an unexpected problem: instead of enhancing the reaction, the applied electric field appears to inhibit it, contrary to both the literature calculations and experimental results.
The reference I used for comparison employed ADS software. Interestingly, I found a note on the ADS official website stating: “The calculation of reactions under applied electric fields in LAMMPS using reactive force fields considers only the force of the electric field, without accounting for the energy of the electric field.（ReaxFF-弹性墙壁：添加外电场、弹性墙壁 [费米维基]” This may explain why my results are opposite to those from the literature and experiments.
I would greatly appreciate any insights or guidance from you regarding this issue. Below is the input script I used for my calculations.
Thank you in advance for your help!
units real
dimension 3
boundary p p f
neighbor 2 bin
neigh_modify every 10 delay 0 check yes
timestep 0.1
atom_style full
pair_style reaxff NULL safezone 5.0 mincap 600 minhbonds 1000
variable T equal 3000.0
variable r_p string “result/0.04”
variable Ez equal 0.04
log ${r_p}/logout.lammps
read_data H2O_c.data
fix zwalls all wall/reflect zlo EDGE zhi EDGE
pair_coeff * * ffield.reax.CHON C N O H
fix 1 all qeq/reaxff 1 0.0 10.0 1.0e-6 reaxff
min_style sd
minimize 1e-8 1e-8 10000 10000
velocity all create 300.0 4928459 rot yes dist gaussian
reset_timestep 0
thermo 200
thermo_style custom step temp pe ke v_Ez
thermo_modify flush yes
fix 2 all nvt temp 300.0 300.0 10
fix 3 all reaxff/species 1 1 200 {r_p}/NVT.out element C N O H cutoff 3 3 0.5
fix 4 all reaxff/bonds 200 {r_p}/bonds_nvt.txt
dump 1 all xyz 200 ${r_p}/NVT.lammpstrj
dump_modify 1 element C N O H
run 200000
unfix 2
unfix 3
unfix 4
undump 1
reset_timestep 0
fix 5 all nvt temp 300 {T} 10.0
fix 6 all reaxff/species 1 1 200 {r_p}/heat.out element C N O H cutoff 3 3 0.5
fix 7 all reaxff/bonds 200 ${r_p}/bonds_heat.txt
run 200000
unfix 5
unfix 6
unfix 7
reset_timestep 0
fix e all efield 0.0 0.0 v_Ez
fix t all nve
fix 8 all temp/berendsen {T} {T} 1000
dump 2 all xyz 200 {r_p}/gas.lammpstrj
dump_modify 2 element C N O H
fix 9 all reaxff/species 1 1 200 {r_p}/gas.out element C N O H cutoff 3 3 0.5
fix 10 all reaxff/bonds 200 ${r_p}/bonds_gas.txt
run 5000000