Molecular dynamics simulation of self-diffusion coefficient and its relation with temperature using simple Lennard-Jones potential

Diffusion coefficient is indispensable to chemical engineering design and research.However,there is great lack of such data.By the means of molecular dynamics simulation,self-diffusion coefficient for simple fluid has been simulated using Green-Kubo relation(VACF: velocity autocorrelation function) and Einstein relation(MSD: mean square displacement).The simulation results make good agreement with experimental findings except an error of about 10%. And,the average of simulation results of the two methods(average) reduces the error to 7%.The relation of diffusion coefficient with temperature has also been simulated.According to simulation results,whose correlation is all above 0.99,diffusion coefficient agrees well with temperature following Arrenhius relation.Activation energy for self-diffusion has been calculated and the results are 1 258 J/mol(VACF),1 272 J/mol(MSD) and 1 265 J/mol(average) separately.