Molecular Dynamics Simulation Based On LAMMPS

Molecular dynamics(MD)is a computational method based on classical mechanics,which mainly describes various characteristics of molecules by the molecular force field.Molecular dynamics simulation has accepted a rapid development in recent years,has been widely used in chemistry,chemistry,physics,biomedicine and other scientific and technical fields.This method is often used to study the microscopic properties and mechanical properties of composite systems which cannot be solved by analytical methods.It is a bridge between theory and experiment.In this paper,MD simulation was used to explore the microscopic characteristics of methane and polymer,as follows:Part one:Using LAMMPS software,molecular dynamics simulation technology is used to study methane in NVT ensemble.The microscopic characteristics of radial distribution function,mean azimuth shift,velocity autocorrelation function and diffusion coefficient were compared with the experimental results and numerical results of other researchers,and the results were analyzed.The simulation results show that our results are highly consistent with the experimental results,and MD simulation can well predict the microscopic properties of methane such as radial distribution function and diffusion coefficient.The results give us a better understanding of the microscopic properties of methane.Part two:Molecular dynamics simulations were performed on a star polymer with the same chemical structure.In the simulation process,each molecule of star polymer was regarded as a single coarse-grained(CG)particle,and the three situations of star polymer were simulated under the NVT ensemble,so as to obtain the microscopic trajectory under the action of coarse-grained.The results were compared with the existing literature,and the data of the three situations were analyzed respectively.The results show that the simulation of star polymer in coarse granulation is feasible.