| 1. |
- Marimuthu, Aravindh N., et al.
(author)
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Laboratory gas-phase vibrational spectra of [C3H3]+ isomers and isotopologues by IRPD spectroscopy
- 2020
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In: Journal of Molecular Spectroscopy. - : Elsevier BV. - 0022-2852 .- 1096-083X. ; 374
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Journal article (peer-reviewed)abstract
- Gas phase vibrational spectra of [C3H3]+ isomers and their fully deuterated isotopologues measured in a cryogenic 22-pole ion trap are presented. The widely tunable free electron laser for infrared experiments, FELIX, was employed to cover the frequency range 500–2400 cm−1, complemented with an OPO/OPA system covering 2800–3400 cm−1. Spectral assignments for both the linear and cyclic isomeric form (H2C3H+ and c-C3H3+, respectively) are made based on various high-level computational studies. The effect of ion source conditions and different precursors (allene and propargyl chloride) for the preferential production of a specific isomer is discussed. The perturbation of the vibrational band position due to complexation with neon in the recorded infrared-predissociation (IRPD) spectra are also reported in this study.
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| 2. |
- Roth, Lorenz, et al.
(author)
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An attempt to detect transient changes in Io's SO2 and NaCl atmosphere
- 2020
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In: Icarus. - : Elsevier BV. - 0019-1035 .- 1090-2643. ; 350
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Journal article (peer-reviewed)abstract
- Io's atmosphere is predominately SO2 that is sustained by a combination of volcanic outgassing and sublimation. The loss from the atmosphere is the main mass source for Jupiter's large magnetosphere. Numerous previous studies attributed various transient phenomena in Io's environment and Jupiter's magnetosphere to a sudden change in the mass loss from the atmosphere supposedly triggered by a change in volcanic activity. Since the gas in volcanic plumes does not escape directly, such causal correlation would require a transient volcano-induced change in atmospheric abundance, which has never been observed so far. Here we report four observations of atmospheric SO2 and NaCl from the same hemisphere of Io, obtained with the IRAM NOEMA interferometer on 11 December 2016, 14 March, 6 and 29 April 2017. These observations are compared to measurements of volcanic hot spots and Io's neutral and plasma environment. We find a stable NaCl column density in Io's atmosphere on the four dates. The SO2 column density derived for December 2016 is about 30% lower compared to the SO2 column density found in the period of March to April 2017. This increase in SO2 from December 2016 to March 2017 might be related to increasing volcanic activity observed at several sites in spring 2017, but the stability of the volcanic trace gas NaCl and resulting decrease in NaCl/SO2 ratio do not support this interpretation. Observed dimmings in both the sulfur ion torus and Na neutral cloud suggest rather a decrease in mass loading in the period of increasing SO2 abundance. The dimming Na brightness and stable atmospheric NaCl furthermore dispute an earlier suggested positive correlation of the sodium cloud and the hot spot activity at Loki Patara, which considerably increased in this period. The environment of Io overall appears to be in a rather quiescent state, preventing further conclusions. Only Jupiter's aurora morphology underwent several short-term changes, which are apparently unrelated to Io's quiescent environment or the relatively stable atmosphere.
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| 3. |
- Sundelin, David, et al.
(author)
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Spectroscopic characterisation of the isomeric H2NCH+ and H2CNH+ radical cations
- 2022
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In: Journal of Molecular Spectroscopy. - : Elsevier BV. - 0022-2852 .- 1096-083X. ; 387
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Journal article (peer-reviewed)abstract
- The vibrational transitions and the relative abundances of the two isomeric ions H2CNH+ and H2NCH+ generated through electron impact ionisation have been investigated in a noble gas tagging experiment. It could be shown that both species were formed with an abundance of 70 and 30% for H2NCH+ and H2CNH+, respectively. The obtained vibrational bands of the two species have been assigned to vibrational transitions through comparison with the results of ab initio calculations. These computations also predict both species to be moderately polar. The present investigations show that both isomers should be included in chemical model calculations of dark interstellar clouds, protoplanetary disks, star-forming regions as well as planetary atmospheres.
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