Among the investigated NPs, To 309 (Figure ) is one of the most interesting. In fact, the To 309 arrangement is known to be a non-favorable FCC arrangement. Indeed, To 309 is more dynamic than Dh 348 at all investigated temperatures(see also Supplementary Movie 3). Interestingly, at 300 K this NP is found less stable and more dynamic than Ih 309 , with ∼ 24% of its surface atoms in non-native AEs (pie charts in Figure and histograms of Figure ). However, at 500 K, To 309 is found more stable than Ih 309 and its surface shows "discrete" atomic dynamics. Raw transition matrices for Dh 348 and To 309 are provided in Supplementary Figure and Supplementary Figure .