Diagram C13 shows the resulting energy as a function of particle size, which is constant down to 5nm, but rises dramatically below 2.5 nm. In addition, these particles change shape frequently, on the second time scale, under observation by high resolution electron microscopy. This SEM picture is of the same type of crystal used to establish the equilibrium form, as discussed in my ASU lecture 1.2 . Pb crystals of a similar size indicates both how face-specific these arguments can be, and also that there may be severe nucleation problems before the reactions can be nucleated. There are many reasons why one would want to follow such reactions at higher pressures, in order to simulate the conditions of real catalysts.
Optical observation is advantageous, even if the spatial resolution is limited.
We can clearly expect further developments of this type in future.