TY - JOUR
T1 - Complex Ice Chemistry: A comparative study of electron irradiated planetary ice analogues containing methane
AU - Kipfer, Kristina A.
AU - Galli, André
AU - Riedo, Andreas
AU - Tulej, Marek
AU - Wurz, Peter
AU - Ligterink, Niels F.W.
PY - 2024
Y1 - 2024
N2 - Various Solar System objects are covered in layers of ice that are dominated by H
2O, CH
4, and N
2 and in which complex chemical processes take place. In this work, the influence of composition and irradiation duration on the volatile irradiation products of mixed CH
4:N
2, CH
4:H
2O, and CH
4:H
2O:N
2 ices after electron irradiation are studied. The ices were irradiated for 2 or 4 h with 5 keV electrons, followed by a temperature programmed desorption, where the desorption of the volatile irradiation products was observed. The formation of C
2H
x and C
3H
x is observed in all ices and for both irradiation times. For the ices containing H
2O, molecules as large as tentatively identified C
4H
x and C
5H
x are observed to co-desorb with water, whereas for CH
4:N
2 a continuous desorption signal is observed instead of a sharp desorption peak. A decrease in signal intensity from the 2 to the 4 h irradiation is observed for most m/z signals in CH
4:H
2O and CH
4:H
2O:N
2 ices, whereas the opposite is recorded for CH
4:N
2, where in general larger signal for longer irradiation duration is seen. The addition of nitrogen to the CH
4:H
2O ice did not lead to clear identification of different molecules, but instead to a decrease of the observed signal for complex molecules, suggesting that the addition of nitrogen to the CH
4:H
2O mixture primarily leads to a more effective incorporation of material in an organic residue. The analysis of the residue will be subject of future work to complement the findings in this study.
AB - Various Solar System objects are covered in layers of ice that are dominated by H
2O, CH
4, and N
2 and in which complex chemical processes take place. In this work, the influence of composition and irradiation duration on the volatile irradiation products of mixed CH
4:N
2, CH
4:H
2O, and CH
4:H
2O:N
2 ices after electron irradiation are studied. The ices were irradiated for 2 or 4 h with 5 keV electrons, followed by a temperature programmed desorption, where the desorption of the volatile irradiation products was observed. The formation of C
2H
x and C
3H
x is observed in all ices and for both irradiation times. For the ices containing H
2O, molecules as large as tentatively identified C
4H
x and C
5H
x are observed to co-desorb with water, whereas for CH
4:N
2 a continuous desorption signal is observed instead of a sharp desorption peak. A decrease in signal intensity from the 2 to the 4 h irradiation is observed for most m/z signals in CH
4:H
2O and CH
4:H
2O:N
2 ices, whereas the opposite is recorded for CH
4:N
2, where in general larger signal for longer irradiation duration is seen. The addition of nitrogen to the CH
4:H
2O ice did not lead to clear identification of different molecules, but instead to a decrease of the observed signal for complex molecules, suggesting that the addition of nitrogen to the CH
4:H
2O mixture primarily leads to a more effective incorporation of material in an organic residue. The analysis of the residue will be subject of future work to complement the findings in this study.
UR - http://www.scopus.com/inward/record.url?scp=85169831800&partnerID=8YFLogxK
U2 - 10.1016/j.icarus.2023.115742
DO - 10.1016/j.icarus.2023.115742
M3 - Article
SN - 0019-1035
VL - 410
JO - Icarus
JF - Icarus
M1 - 115742
ER -