Volatile silicon compounds (VOSiCs) are air pollutants present in both indoor and outdoor environments. Here, tetramethylsilane (TMS) is selected as a model to study the photochemical oxidation mechanisms for VOSiCs using ab initio and RRKM theory/master equation kinetic modeling. Under tropospheric conditions, the radical (CH3)(3)SiCH2 center dot reacts with O-2 to produce a stabilized peroxyl radical, which is expected to ultimately yield the alkoxyl radical (CH3)(3)SiCH2O center dot. At combustion-relevant temperatures, however, a well-skipping reaction to (CH3)(3)SiO center dot + HCHO dominates. Importantly, the (CH3)(3)SiCH2O center dot radical is predicted to rearrange to (CH3)(3)SiOCH2 center dot with a very low reaction barrier, enabling an auto-oxidation process involving addition of a second O-2. Subsequent oxidation reaction mechanisms of (CH3)(3)SiOCH2 center dot have been developed, with the major product predicted to be the trimethylsilyl formate (CH3)(3)SiOCHO, an experimentally observed TMS oxidation product. The production of substantially oxygenated compounds following a single radical initiation reaction has implications for the ability of VOSiCs to contribute to ozone and particle formation in both outdoor and indoor environments.