I am trying to find the transport diffusion in zeolite pores. First of all i need to find out the fagucity of associated gas molecules in zeolite pores according to the Darken equation. Please help me to investigate the appropriate method to calculate the gas’s fagusity.

Search the literature to see how others use Darken equation in an MD. Then look through LAMMPS’ commands to see if you can use LAMMPS to perform such task.