For coke to form, dehydrogenation must proceed further, beyond acetylene. With acetylene bound to Pt4Ge (Fig. ), the isomer populations adjust again: the LM' isomer drops even further in energy relative to the GM, such that its P700K increases to ~10% of the total population. The population dehydrogenates acetylene with a high propensity, rather than desorbing it, as suggested by the fact that in a number of the low-lying isomers of C2H2-Pt4Ge/alumina, acetylene dehydrogenates spontaneously (Fig. ). For the thermally accessible isomers in which C2H2 remains intact, the computed first C-H dissociation barriers are well below the desorption energies for intact acetylene, which exceed 2 eV from all isomers (Fig. ). Notably, LM'-based isomers continue to dehydrogenate more aggressively than GM-based isomers, judging by the computed barriers, and new Pt4Ge core isomers are stabilized due to the strong binding of acetylene, provide lower-barrier routes for dehydrogenation (Fig. , dashed lines).