Study of Equation-of-State of Dense Helum by Molecular Dynamics Simulation

The optimized value of =12.7, which is the stiffness parameter in exponential 6 potential function used for describing the compression behavior of dense helium, is determined by means of molecular dynamics simulation and makes comparison with the experimental isotherm of solid helium. Then, we adopt this new value of to calculate the equation of state and the radial distribution function for fcc solid helium at high temperatures, and find while =1.60 g/cm3 the second peak of the radial distribution function would disappear in the regime of 2 000 K to 3 040 K. It demonstrates the long-rang degree of order is degraded or the solid-liquid transition occurs under that condition.