Figure 3.

(a) Schematic illustration showing that the interfacial dynamics of water can only be understood at the nanometer length-scale while the relevant timescale for molecular diffusion is the pico- to nanosecond regime. (b) The ps to ns regime is covered with scattering techniques [S] (quasi-elastic neutron and helium scattering: QENS/QHAS), while longer timescales are accessible with scanning probe microscopy [M] (STM/AFM). Optical techniques [O] such as PEEM can provide the temporal resolution via pulse-synchronised methods but are limited in terms of their lateral resolution.