Classical molecular dynamics simulation with the Velocity Verlet algorithmat strong external magnetic fields

We present a new method for incorporating arbitrarily strong static homogen eous external magnetic fields into molecular dynamics computer simulations. Conventional techniques dealing with magnetic fields demand the simulation time step Delta t to be small compared to the Larmor oscillation time 2 pi /Omega. In our method, in contrast. the magnetic field is built into the pr opagation equations in such a way as to make the choice of Delta t entirely independent of 2 pi/Omega. Thus, the time step is determined only by the i nternal physical properties of the system under consideration. This propert y of our method is essential for simulating strongly magnetized systems of charged particles in an efficient way. The method is developed in the frame work of the second-order Velocity Verlet propagation scheme. However, the u nderlying concept is independent of this choice, and a generalization to ar bitrary order without any reference to a specific propagation scheme is als o given. (C) 1999 Academic Press.