Direct Observation of Molecular Oxygen Production from Carbon Dioxide

Oxygen ($O_2$) is one of the most important elements required to sustain life. The concentration of $O_2$ on Earth has been accumulated over millions of years and has a direct connection with that of $C{O}_2$. Further, $C{O}_2$ plays an important role in many other planetary atmospheres. Therefore, molecular reactions involving $C{O}_2$ are critical for studying the atmospheres of such planets. Existing studies on the dissociation of $C{O}_2$ are exclusively focused on the C–O bond breakage. Here we report first experiments on the direct observation of molecular Oxygen formation from $C{O}_2$ in strong laser fields with a reaction microscope. Our accompanying simulations suggest that $C{O}_2$ molecules may undergo bending motion during and after strong-field ionization which supports the molecular Oxygen formation process. The observation of the molecular Oxygen formation from $C{O}_2$ may trigger further experimental and theoretical studies on such processes with laser pulses, and provide hints in studies of the $O_2$ and $C{O}_2^{+}$ abundance in $C{O}_2$-dominated planetary atmospheres.