The interaction of CO2 molecules with the Si(111)7×7 surface for translational energies between 0.2 and 1.6 eV and varying vibrational energies has been studied with time-resolved electron-energy-loss spectroscopy (TREELS), temperature-programed desorption, and Auger electron spectroscopy. Energy from the normal component of translational motion has been found to strongly increase the dissociation probability of CO2 on the surface. TREELS has been used to tentatively identify the resulting surface complex as O on a Si adatom with CO bonded in a bridging site to a next-layer Si rest atom. This complex decomposes at 400 K to a surface oxide and gas-phase CO. In addition, vibrational excitation has been found to increase the initial sticking coefficient for normal translational energies less than 0.5 eV.