Hi everyone,

I would like to ask a question regarding the calculation of ionic conductivity in electrolytes.

As shown in the attached paper (J. Phys. Chem. Lett. 2023, 14, 7718–7731; see the link below), there are two different approaches to calculate ionic conductivity: the Nernst–Einstein equation and the Green–Kubo relation.

The conductivity from the Nernst–Einstein equation is relatively straightforward to obtain using the MSD curve to extract the diffusion coefficient.
(1. Define the cation and anion, respectively;
(2. Obtain the diffusion coefficients using the analysis module in Forcite;
(3. Calculate the conductivity from the diffusion values.)

However, the Green–Kubo relation considers the correlated motion between ions. In the Forcite analysis interface, I can find a single correlation function option — but I couldn't find a way to specify ion i and j pairs as required in Eq. (4) of the paper.

Is there any way to compute the conductivity following Eq. (4) in Forcite, or should I extract and analyze the velocity trajectories manually?

My previous related question is here → 

Any advice would be greatly appreciated. Thank you!

Best regard,

Hongjun Chang