The translational order parameter, τ, was then determined using the distribution of a suitable reference atom within the molecules along the overall layer-normal vector using Equation , where z is the position of a reference atom projected onto the overall layer-normal vector, d is the layer spacing, which is optimised to give the highest value of τ for each trajectory frame, L is the length of the box used in the analysis, and the angular brackets denote an ensemble average for that frame. The radial distribution function, g(r) (Equation ) reports on the relative probability of distances, rij, between a reference point on molecule i and the equivalent point on molecule j, ρN is the average number density of the system, and δ is the Dirac Delta function.