A summary of the results obtained on the barrier to stalk formation and the depth of the stalk free energy minimum (which are both calculated with respect to the pre-stalk state).

NP core diameter (nm)	Height of the barrier (kJ mol−1)	Stalk minimum depth (kJ mol−1)
2	19.5 ± 1	−33 ± 2
3	22 ± 1	−8.5 ± 1
4	26 ± 1	0 ± 1