can LAMMPS compute electrical conductivity, similarly to mean-square displacement

Hello LAMMPS community,

I came across this paper,

Levesque, Maximilien, et al. “Structure and dynamics in yttrium-based molten rare earth alkali fluorides.” The Journal of chemical physics 138.18 (2013): 184503.

and found the Equation (2) to compute the electrical conductivity,Screenshot from 2016-12-01 12-50-41.png
This equation is very similar with the Einstein-Smoluchowski relation, which relates the self-diffusivity coefficient to mean-square displacement of MD simulation
Screenshot from 2016-12-01 12-50-28.png

My question is how can I compute the quantities in Equation (2) in LAMMPS? Is there an analogous compute for atomistic charges, as in ‘compute msd’ command at Please let me know if so.

Many thanks,
Anh Tran

No, I think you’d have to write a new compute for that,

or add an optional keyword to compute msd to include

a “multiply by q” for each atom in the summation.


Screenshot from 2016-12-01 12-50-41.png

Screenshot from 2016-12-01 12-50-28.png


Thank you for
hat’s a good idea. I think I’m just going to write a new compute based on compute_msd.h/.cpp, but before I proceed, would you please confirm that I can simply change the keyword from this line of the header file compute_msd.h, and name of the class in C++, and start adding code in the corresponding .cpp file?

Screenshot from 2016-12-01 12-50-41.png

Screenshot from 2016-12-01 12-50-28.png