SYMPLECTIC INTEGRATORS FOR LARGE-SCALE MOLECULAR-DYNAMICS SIMULATIONS- A COMPARISON OF SEVERAL EXPLICIT METHODS

We test the suitability of a variety of explicit symplectic integrator s for molecular dynamics calculations on Hamiltonian systems. These in tegrators are extremely simple algorithms with low memory requirements , and appear to be well suited for large scale simulations. We first a pply all the methods to a simple test case using the ideas of Berendse n and van Gunsteren. We then use the integrators to generate long time trajectories of a 1000 unit polyethylene chain. Calculations are also performed with two popular but nonsymplectic integrators. The most ef ficient integrators of the set investigated are deduced. We also discu ss certain variations on the basic symplectic integration technique.