units and diffusion coefficient please help


I have a question regarding lammps. I am trying to find the diffusion coefficient through the MSD and Einstein equation. I did the simulation; however, I still have a question regarding a specific matter which is c_msdco2[4] what does it represents and in what unit I have the same thing but c_msdco2[3], c_msdco2[2],c_msdco2[1].

I would really appreciate your reply.


The unit system in LAMMPS is set by the user via the command “units”. You can find all details in the link https://lammps.sandia.gov/doc/units.html


Στις Τρίτη, 16 Απριλίου 2019, ο χρήστης President LDA UAE <[email protected]…8238…> έγραψε:

And as the doc page for compute msd explains, all those quantities are
in units of distance squared. I.e. mean squared displacements.
As the previous responder noted, “distance” is defined by the “units” command.