Abstract: Common formulae for the free-order explicit multistep method of precise time integration are proposed. When the higher order explicit algorithms of precise time integration are applied for calculating the ray equation and the classical trajectories of diatomic system, the effect is admirable. The numerical results reveal that the pressent method is higher accurated and efficient, capable of keeping computational stability for long time simulation, and suitable for higher order numerical computation.

Key words: free-order multi-step method of precise integration, higher order numerical computation, classical trajectory stability analysis