Molecular dynamics studies of shock wave propagation in argon by using higher order symplectic integrators

The generation and propagation of shock waves in liquid Ar are investigated using the molecular dynamics method by means of higher order symplectic integrators (H. Yoshida, 1990, [12]). The symplectic integrator is the numerical integration scheme for Hamiltonian systems. The algorithm is accurate and has no accumulation of numerical errors for total energy. In order to test the effect of higher order symplectic integrators on molecular dynamics, we have calculated NVE ensemble in liquid argon. The results obtained by using the two integrators (Verlet and sixth symplectic methods) are compared. It is clearly shown that the total energy decreases considerably by using Verlet method, while it is fairly well conserved the total energy with the symplectic method. Furthermore, we have calculated the generation and the propagation of plane shock wave in liquid Ar. It has been found that the profiles of shock wave front using higher order symplectic integrators steeper and narrower compared to the Verlet method.