  Room temperature ionic liquids (RTILs) are solvent with unusual properties,
which are difficult to characterize experimentally because of their intrinsic
complexity (large number of atoms, strong Coulomb interactions). Molecular
simulations have therefore been essential in our understanding of these
systems. Depending on the target property and on the necessity to account for
fine details of the molecular structure of the ions, a large range of
simulation techniques are available. Here I focus on classical molecular
dynamics, in which the level of complexity of the simulation, and therefore the
computational cost, mostly depends on the force field. Depending on the
representation of the ions, these are either classified as all-atom or
coarse-grained. In addition, all-atom force fields may account for polarization
effects if necessary. The most widely used methods for RTILs are described
together with their main achievements and limitations.
