High Energy Radical Chemistry Formation of HCN-rich Atmospheres on early Earth.
Several simple inorganic and organic compounds were identified in the reaction mixture exposed to ten laser sparks. The chemical consequences of laser-produced plasma generation in a CO−N 2−H 2O mixture were investigated using high resolution Fourier-transform infrared absorption spectroscopy (FTIR) and gas chromatography (GC). However, carbon monoxide cations were registered only if their production was enhanced by Penning ionization, i.e., excess He was added to the CO. Special attention was paid to any OES signs of molecular ions. The excited reaction intermediates that formed in various stages of the LIDB plasma chemical evolution were investigated by optical emission spectroscopy (OES) with temporal resolution. A multiple-centimeter-sized fireball was created by focusing a single 85 J, 450 ps near-infrared laser pulse into the center of a 15 L gas cell. The composition of the mixtures used corresponded to a cometary and/or meteoritic impact into the Earth’s early atmosphere. Large-scale plasma was created in gas mixtures containing carbon monoxide by high-power laser-induced dielectric breakdown (LIDB).