  We extend the use of the adaptive resolution method (AdResS) in its Grand
Canonical-like version (GC-AdResS) to the molecular dynamics simulation of
1,3-dimethylimidazolium chloride. We show that the partitioning of the total
system in a subsystem of interest with atomistic details and a reservoir of
coarse-grained particles leads to satisfactory results. The challenging aspect
of this study, compared to previous AdResS simulations, is the presence of
charged particles and the necessity of addressing the question about the
minimal physical input needed to model the coarse-grained particles in the
reservoir. We propose two different approaches and show that in both cases they
are sufficient to capture the decisive physical characteristics that allow a
valid system-reservoir coupling. The technical satisfactory result paves the
way for multiscale analysis of ionic liquids and for truly open boundary
molecular simulations.
