20-EPN2-090 – A Search for Thiols Formation Pathways Under Space-Relevant Conditions
April 26, 2024

20-EPN2-090 – A Search for Thiols Formation Pathways Under Space-Relevant Conditions

Visit by Zuzana Kaňuchová (Astronomical Institute of the Slovak Academy of Sciences, Slovakia) and Tom Field (Queen’s University Belfast, UK) TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 27 November – 8 December 2023

Report Summary: Despite being only the tenth most abundant element in space, sulfur is a component of several biomolecules, making it a key subject for astrochemistry studies. Sulfur containing molecules were observed in the solid phase on the surfaces of icy moons and in the icy mantles of interstellar grains. Despite the seemingly ubiquitous detection of sulfur-bearing species in space, the sulfur budget is still puzzling the scientific community. To address this, Zuzana Kaňuchová and Tom Field conducted an exploratory series of irradiation experiments to determine if species with thiol (-SH) groups may be formed in hydrocarbon-rich ices at temperatures relevant to interstellar matter, the surfaces of Solar System icy satellites, and Kuiper Belt objects.

They implanted 200 keV S+ ions in methane (CH4), ethane (C2H6), ethene (C2H4), and ethyne (C2H2) ices at 20 K and 60 K. Formation (and destruction) of species was monitored via FTIR spectroscopy and quadrupole mass spectrometry. Based on preliminary analysis performed during the TA they decided to conduct one extra (supplementary) experiment to explore the possibility of forming carbon and sulfur-bearing molecules by implanting high-energy carbon (750 keV) ions into hydrogen sulfide (H2S).
The preliminary analysis does not indicate the formation of thiols in the investigated hydrocarbon ices as a result of high-energy sulfur ions implantation. However, several new absorption bands appeared in the
spectra of all irradiated hydrocarbons, indicating the formation of various alkanes and alkenes. The emergence of a prominent band around ~1600 cm-1 could suggest the presence of carbon in an amorphous form.