Light olefins (ethylene and propylene) are the fundamental building blocks of the petrochemical industry. The molecules are readily available and can be converted to a wide range of useful intermediate and final products. The production of short linear alpha olefins (LAOs), in particular, has been of significant interest in the olefin industry for the past few decades, as they form the key ingredients of various plastics, lubricants, fuels, and surfactants. Production of LAOs, such as 1-butene, 1-hexene, and 1-octene, through selective catalytic olefin oligomerization has, in turn, become a core research topic in the olefin community due to the existence of many emerging alternative sources of light olefins and the increasing demand for polyethylene. Presently, homogeneous catalysts, using ligand-modified transition metals, are among the most active and selective catalysts for olefin oligomerization. Among the transition metals, nickel complexes are commonly used, where the Ni 2+ compounds modified with alkyl or hydride moieties are the catalytic centers responsible for olefin oligomerization. Many efforts have also been devoted to developing heterogeneous catalysts for olefin oligomerization, given their greater facility for catalyst regeneration and product separation. As an example, reactive transition metal species, inspired by analogous structures on homogeneous catalysts, can be supported on porous structures, such as zeolites and amorphous silica, but these catalysts suffer from poor oligomerization activity or low selectivity to LAOs. Density functional theory (DFT)-based studies are becoming increasingly important in elucidating the structures and properties of active sites, as well as the reaction mechanisms, of heterogeneously catalyzed olefin oligomerization processes. For instance, a recent firstprinciples study by Brogaard et al. investigated Ni(0), Ni + , and Ni 2+ supported on an SSZ-24 framework in the context of ethylene oligomerization. The work revealed that the most plausible pathway starts from a [Ni(II)-ethylene-H] + complex, analogous to a Ni-alkyl ligand in the homogeneous context, and the oligomerization chemistry follows the classic Cossee-Arlman (C-A) mechanism, where ethylene coordinates and inserts between the species and the Ni ion, resulting in chain growth. The process is terminated via an ethylene-assisted β-hydride elimination step that restores the [Ni(II)-ethylene-H] + moiety. In another mechanistic study by Metzger et al., investigating Ni-MFU-4l for ethylene dimerization, a combination of isotope tracing, molecular probes, and DFT calculations were used to demonstrate that the catalytic cycle also follows a C-A mechanism, where ethylene insertion and β-hydride elimination are the key elementary steps. To expand the space of possible heterogeneous catalysts for olefin oligomerization, singlesite, silica-supported main-group Ga ions have recently been explored and found to selectively catalyze ethylene and propylene oligomerization to higher molecular weight linear olefins, up to at least C18, at 250 °C and an atmospheric pressure. Through a combination of in-situ and ex-situ X-ray absorption spectroscopy (XAS), H/D exchange, IR techniques, and DFT calculations, it was determined that Ga 3+ sites catalyze the oligomerization reaction. The mechanism starts from a site activation process, where a Ga 3+ -O bond is activated, resulting in Ga-vinyl and Si-OH moieties (species 1 to 2, Fig. ). After the activation step, ethylene insertion and β-hydride elimination occur, leading to butadiene and a Ga-hydride site (species 6b, Fig. ). The Ga-hydride was proposed to be responsible for the subsequent oligomerization cycle, following a C-A mechanism (cycle c, Fig. ). To further elucidate the mechanistic and structural aspects of oligomerization on Ga-based silica catalysts, it is of interest to explore whether additional factors, such as the intrinsic heterogeneity of amorphous silica, can accommodate activation of other oligomerization pathways.