Relationship between the Permeation-Diffusion Parameters of a Single-File Channel

Two sets of widely used parameters can describe the molecular permeation through a nanochannel. One is permeation rate j and its diffusion D_n, and the other is flow and net flux. We establish a relationship between the two sets for a single-file nanochannel, as well as its dependence on the temperature and pressure difference between the two ends of a single-file channel, based on the Brownian motion theories and verified with molecular dynamics simulations for the water diffusion in a transmembrane (6,6) armchair carbon nanotube. Simulation results are in excellent agreement with our predictions.