Molecular Dynamics Simulation on Microscopic Characteristics of Carbon Dioxide in Trans-Critical Progress

Molecular dynamics (MD) simulations was performed to analyze the microscopic characteristics of carbon dioxide in trans-critical progress. Radial distribution function (RDF) analysis exhibited that the short-range structure varied weakly near the critical point, which was mainly enhanced by the strong neighbor intermolecular interaction. The simulation results of the coordination number in first shell further show that the variation of short-range structure primarily lies in the number change of coordinated molecular; The gaseous CO2 is still of an ordered structure in the short-range and of a disordered structure in the long-range; The static structure factor analysis showed the existence of medium/long-rang ordered structure. Disorder range was defined and its abrupt surge showed explicitly that the range of intermolecular interaction increased in the pseudo-critical region.