Formation of C2 organic molecules from CO₂ and H₂O by femtosecond laser induced chemical reactions in water

Formation of C-C bonds was induced by femtosecond (fs) laser irradiation in CO₂-saturated ultrapure water. In addition, fs-laser irradiation of aqueous HCOOH or (COOH)₂ solution purged with CO₂ or Ar generated larger molecules. Isotope experiments confirmed the certainty of the reactions. On the other hands, nanosecond (ns) laser irradiation produced CO only in ultrapure water, and fs-laser irradiation in gas-phase CO₂ in the presence of water produced CO and H₂ only. Discussion excluded possibility of direct interaction of laser light with CO₂ molecules, ionization of molecules in water, and high temperature plasma formation. As a consequence, it is strongly suggested that formation of these organic molecules could be due to fs-laser induced shock wave exposure to CO₂ molecules surrounded by water molecules.