Extended kinetic lattice grand canonical Monte Carlo simulation method for transport of multicomponent ion mixtures through a model nanopore system

摘要

An extended version of the original kinetic lattice grand canonical Monte Carlo simulation method combined with mean field theory(KLGCMC/MF)(J.Chem.Phys.2007,127,024706)is presented for the study of transport of multicomponent ion mixtures through a model nanopore.Comparison of the extended KLGCMC/MF(eKLGCMC/MF)simulation results with Poisson-Nernst-Planck(PNP)calculations is also made to confirm the validity of the extended simulation approach.Unlike the original version of KLGCMC/MF simulation method that treats only a binary ionic solution with one cation and one anion species,this extended version can deal with a system that includes ternary ion mixtures.A diffusion probability algorithm is also added to the extended version of the simulation method to describe the inhomogeneous diffusivity of ions that is often observed in the ion permeation through nanopores.Both Legendre and Chebyshev polynomials of the second kind were tested as a basis set for the basis set expansion(BSE)method with which to calculate the reaction field energy in the eKLGCMC/MF simulation.It turned out that the Legendre polynomials perform better than the Chebyshev polynomials,and as a result,the Legendre polynomials were implemented in the current version of eKLGCMC/MF simulation algorithm.The presented eKLGCMC/MF simulation method with new features finds its potential applications in nanopore systems where the correlation between ion species with the same sign of charges plays a key role such as oscillating ion currents or anomalous mole fraction effects.