Dear all

while calculating the thermal conductivity using green kubo method of liquid electrolyte having bond angle, dihedral angle, improper angle, I got error KSpace style does not support compute centroid/stress/atom.

I used kspace_style pppm 1.0e-4

when i tried to calculate thermal conductivity with **compute stress/atom** simulation is running with same kspace style.

In the LAMMPS manual it is clearly written that compute centroid/stress/atom must be used if in your system having bond angle, dihedral angle, improper angle.

please help me to short out to this problem. thanks in advance

There is nothing to *short* out (sp!).

The path forward is quite obvious. You have multiple choices:

thanks for your kind reply

there is any reference or article to drive the expression for computing per-atom centroid stress from lattice sum and how to implement in LAMMPS

as per my knowledge

step 1. compute the forces acting on each atom(involves summing up all pairwise forces between atoms) using lattice sum approach

step2. compute the stress tensor at each atom using lattice sum approach

σi=(1/Vi)∑(Rij)XFij

step3. compute the per-atom centroid stress by averaging the stress tensors over the neighboring atoms of each atom

σ (centoroid)i= (1/ni)∑σj

input code:

compute myforce all force

compute stress all stress/atom NULL virial

fix mystress all ave/atom 1 100 100 c_stress[1] c_stress[2] c_stress[3] c_stress[4] c_stress[5] c_stress[6] c_stress[7] c_stress[8] c_stress[9] file stress_atom.dat

compute per_atom_stress all reduce ave c_stress[1] c_stress[2] c_stress[3] c_stress[4] c_stress[5] c_stress[6] c_stress[7] c_stress[8] c_stress[9]

fix centoridstress all ave/time 1 1 1 c_per_atom_stress[*] file centroid_stress.dat

this is correct way?

I don’t understand what you are asking here.

My statements are quite clear. If there was more information available and detailed instructions on how to implement the centroid stress for kspace styles, it would probably already exist. This is first and foremost a physics problem.