July 12

Tobias Richard Kliesch (RTG 2450, KIT, Germany)

11:00 - 11:20

Molecular Dynamics simulation is a widely used tool to approximate the behaviour of a many body system, using Newtonian mechanics. The standard integrator for solving Newtons equation of motion is the Verlet scheme. The Verlet integrator has many desirable properties, i.e. symplecticity and symmetry, is easily implemented and parallelized. The largest possible step size is linked to the highest oscillations in the system. This results in a severe restriction for the stepsize in molecular dynamics simulation.
Multiple efforts have been made to overcome this restriction. Larger stepsizes are possible by either constraining (SHAKE) or calculating the higher oscillatory forces separately with smaller stepsize (RESPA). The first approach alters the physical properties of the problem and the second suffers from numerical resonances, which are hard to control.
We introduce a new integrator that integrates the highly oscillatory motions exactly and has a build in resonances control, the trigonometric integrator. Additional challenges arise due to the needed matrixfunction evaluations. We demonstrate an efficient, parallel implementation in LAMMPS and apply it to relevant examples.