For Pt7, similar to the results for ethylene, CO is found to bind substantially more strongly (ΔECO = -2.83 to -2.33 eV) to cluster structures based on the single-layer LM1 isomer of Pt7, compared to CO binding to the prismatic GM isomer (ΔECO = -2.2 to -2.1 eV), such that the lowest energy Pt7-CO structures all have Pt7 in a single-layer configuration. The question is whether binding CO is sufficient to drive the GM-to-single-layer isomerization, and the TPD experiments suggest that it does, at least for a saturation CO dose. This conclusion is based on the numbers of CO molecules that adsorbed per Pt atom in the 1 st CO TPD run, which are similar for Pt4 and Pt7, but substantially lower for Pt11. That suggests that Pt7 adopts a single layer structure, will all Pt atoms exposed upon CO saturation, while