Investigation of laser–plasma chemistry in CO–N2–H2O mixtures using 18O labeled water

A large-scale plasma was created in CO–N2–H2O gas mixtures by high-power laser-induced dielectric breakdown. The composition of the mixtures used corresponded to a cometary and/or meteoritic impact into the Earth’s early atmosphere. A multiple-centimeter-sized fireball was created by focusing near-infrared laser pulse into the centre of cell. The laser–plasma formation in the mixtures mainly leads to a production of CO2. The competition of the CO + CO → CO2 + C and CO + OH → CO2 + H reactions in the CO2 production was investigated using 18O labeled water. An analysis of the isotopomers was carried out by means of high-resolution FTIR spectroscopy.