  Hypothesis A prototypical modelling approach is required for a full
characterisation of the static and equilibrium dynamical properties of confined
ionic liquids (ILs), in order to gain predictive power of properties that are
difficult to extract from experiments. Such a protocol needs to be constructed
by benchmarking molecular dynamics simulations against available experiments.
  Simulations We perform an in-depth study of [C2Mim][NTf2] in bulk, at the
vacuum and at hydroxylated alumina surface. Using the charge methods CHelpG,
RESP-HF and RESP-B3LYP with charge scaling factors 1.0, 0.9 and 0.85, we search
for an optimum non-polarizable force field by benchmarking against
self-diffusion coefficients, surface tension, X-ray reflectivity data, and
structural data.
  Findings Benchmarking, which relies on establishing the significance of an
appropriate size of the model systems and the length of the simulations, yields
RESP-HF/0.9 as the best suited force field for this IL overall. A complete and
accurate characterisation of the spatially-dependent internal configurational
space and orientation of IL molecules relative to the solid and vacuum
interfaces is obtained. Furthermore, the density and mobility of IL ions in the
plane parallel and normal to the interfaces is evaluated and the correlation
between the stratification and dynamics in the interfacial layers is detectable
deep into the films.
