The fact that the solvent dynamics involves both libration and jump-type motions is confirmed by comparing the predicted T1 relaxation times with experimental values in Figure . Given that there are no adjustable parameters, there is excellent qualitative agreement when considering the pair of systems. Recalling that the trends in the experimental data could not be rationalised, the fact that MD simulations correctly predict trends in both 2 H NMR spectra and relaxation data shows that the simulations are correctly capturing the solvent dynamics. Significantly this dynamics is consistently on a fast NMR timescale, with motional correlation times measured in ns, and so the traditional approach of analysing changes in 2 H spectra in terms of intermediate timescale dynamics, cf. Figure , is destined to give misleading results.