Figure shows the energetics of the C-A oligomerization cycle on the two sites: 3CN, and the 4CN Ga with a dehydration step. Among them, the 3CN site generally exhibits a much more favorable energy landscape. Specifically, low activation barriers of both ethylene migratory insertion (3CN: 1.7 eV) and β-hydride transfer (3CN: 1.0 eV) are observed. On the 4CN dehydrated site, the ethylene physisorption steps before insertion and β-hydride transfer have The same species numbers are used in Figure .