0586720 - ÚFCH JH 2025 RIV US eng J - Journal Article
Knížek, Antonín - Petera, Lukáš - Laitl, Vojtěch - Ferus, Martin
Decomposition of HCN during Experimental Impacts in Dry and Wet Planetary Atmospheres.
ACS Earth and Space Chemistry. Roč. 8, č. 6 (2024), s. 1246-1258. ISSN 2472-3452. E-ISSN 2472-3452
R&D Projects: GA ČR(CZ) GA21-11366S; GA MŠMT EF16_019/0000778
Grant - others:ERDF(CZ) CZ.02.1.01/0.0/0.0/16_019/0000778
Institutional support: RVO:61388955
Keywords : hydrogen-cyanide * chemistry * laser * earth * nitrogen * origins * nebulae * planets and satellites: atmospheres * planets and satellites:general * astrochemistry * plasma * shockwaves
OECD category: Physical chemistry
Impact factor: 3.4, year: 2022
Method of publishing: Open access
https://pubs.acs.org/doi/10.1021/acsearthspacechem.4c00064

Hydrogen cyanide (HCN), a key molecule of significant importance in contemporary perspectives on prebiotic chemistry, originates in planetary atmospheres from various processes, such as photochemistry, thermochemistry, and impact chemistry, as well as from delivery by impacts. The resilience of HCN during periods of heavy bombardment, a phenomenon caused by an influx of material on unstable trajectories after accretion, remains relatively understudied. This study extensively investigates the stability of HCN under impact conditions simulated using a laboratory Nd:YAG laser in the ELISE experimental setup. High-resolution infrared spectroscopy was employed to monitor the gas phase composition during these simulations. Impact chemistry was simulated in bulk nitrogen atmospheres with varying mixing ratios of HCN and water vapor. The probed range of compositions spans from similar to 0 to 1.8% of HCN and 0 to 2.7% of H2O in a similar to 1 bar nitrogen atmosphere. The primary decomposition products of HCN are CO and CO2 in the presence of water and unidentified solid phase products in dry conditions. Our experiments revealed a range of initial HCN decomposition rates between 2.43 x 10(15) and 5.17 x 10(17) molec J(-1) of input energy depending on the initial composition. Notably, it is shown that the decomposition process induced by the laser spark simulating the impact plasma is nonlinear, with the duration of the irradiation markedly affecting the decomposition rate. These findings underscore the necessity for careful consideration and allowance for margins when applying these rates to chemical models of molecular synthesis and decomposition in planetary atmospheres.
Permanent Link: https://hdl.handle.net/11104/0354160