Extending timescales

Extending timescales goes hand in hand with many of the themes discussed before, including QM/MM, linear scaling DFT, multiple timestep techniques and biased sampling. Biased sampling makes it possible to observe chemical changes on arbitrary timescales by focusing the evolution of the system on the relevant part of phase space only. While dynamical information is lost, the proper thermodynamics is retained. We have contributed various methods in this broad field, for example biasing QM simulations with classical methods[2], using non-equilibrium molecular dynamics[4,6] and biasing based on properties of the electronic structure.[9] The important concept of performing dynamics on a few-dimensional free energy surface computed on-the-fly, has been introduced in [6], and was one of the sources for metadynamics development.