Emu can study diffusing water molecules or yet larger molecules like polymers or biological molecules. In addition, one can see the quantum-mechanical tunnelling between equivalent orientations of molecular groups. For instance, a CH3- methyl group can typically rotate freely at high temperatures, but at low temperature it locks in to one of three equivalent states.
But, by quantum physics, it can still tunnel from one state to another. This effect manifests itself as an energy splitting, and by measuring the energies and intensities of the resultant spectral features, one can determine the strengths of all the relevant interactions (the Hamiltonian in the Schrödinger Equation) at the microscopic level.