Hey everyone,
I’m currently working on replicating the results from a paper by Yeh and Berkowitz (DOI: [10.1063/1.479595]) using LAMMPS and DPD, focusing specifically on the forces between two particles. While attempting to fine-tune the parameters for the reciprocal space, I encountered some unexpected behavior.
Initially, when I set the kspace_style to ewald with a tolerance of 1e-6, I observed results consistent with those presented in the paper. However, as I experimented with adjusting parameters like gewald and kmax/ewald using the kspace_modify command, I started getting different outcomes. Sometimes, the forces between particles would oscillate, and in other cases, they would steadily increase.
Throughout my experiments, I maintained the same setting of kspace_modify slab 3.0 to ensure consistency.
I’m reaching out for insights into why these variations are occurring. If anyone has experience with LAMMPS simulations or a similar situation, I’d greatly appreciate any advice or suggestions.
Thanks in advance for your help!
Saúl
This is my input:
dimension 3
units lj
atom_style hybrid atomic charge
variable z equal 1.0 #Where i place my particle
region domain block -5 5 -5 5 0 30 units box
create_box 3 domain
change_box all boundary p p f
create_atoms 1 single 0 0 0
create_atoms 2 single 0 0 $z
group pos id 1
group neg id 2
set type 1 charge 1.0
set type 2 charge -1.0
mass * 1.0
pair_style hybrid/overlay coul/long 3.0 dpd 1.0 1.0 419084618
kspace_style ewald 1e-6
#kspace_modify kmax/ewald 1 1 1
#kspace_modify gewald .969
kspace_modify slab 3.0
pair_coeff * * dpd 25.0 4.5
pair_coeff * * coul/long
compute force pos group/group neg kspace yes
thermo_style custom step pe ecoul c_force[*]
thermo 1