IMPROVEMENT OF METHODS FOR MOLECULAR-DYNAMICS INTEGRATION

An application of symplectic implicit Runge-Kutta (RK) integration sch emes, the s-stage Gauss-Legendre Runge-Kutta (GLRK) methods of order 2 s, for the numerical solution of molecular dynamics (MD) equation is d escribed. The two-stage fourth-order GLRK method, the implicit midpoin t rule, and the three-stage diagonally implicit RK method of order fou r are studied. The fixed-point iteration was used for solving the resu lting nonlinear system of equations. The algorithms were applied to a complex system of N particles interacting through a Lennard-Jones pote ntial. The proposed symplectic methods for MD integration permit a wid e range of time steps, are highly accurate and stable, and are thus su itable for the MD integration. (C) 1994 John Wiley & Sons, Inc.