High-order symplectic integration in quasi-classical trajectory simulation: Case study for O( ¹D) + H ₂

Classical trajectory calculations for the O( ¹D) + H ₂ reaction system are employed to assess the effectiveness of the symplectic integrators. The sixth-order symplectic integrator has been found to be the most suitable method for the quasi-classical trajectory calculation of a long-lived complex-forming reaction system. In comparison with the traditional fourth-order Runge-Kutta initialized fourth-order Admas-Moulton-Hamming predictor-corrector integrator (RK4-AMH4), the sixth-order symplectic integrator is six times less computationally expensive and exhibits better energy conservation.