# Carbon chain anions and the growth of complex organic molecules in Titan's ionosphere

@article{Desai2017CarbonCA,
title={Carbon chain anions and the growth of complex organic molecules in Titan's ionosphere},
author={R. Desai and A. Coates and A. Wellbrock and V. Vuitton and F. Crary and D. Gonz'alez-Caniulef and O. Shebanits and G. Jones and G. R. Lewis and J. Waite and S. A. Taylor and D. Kataria and J. Wahlund and N. Edberg and E. Sittler},
journal={The Astrophysical Journal},
year={2017},
volume={844}
}
Cassini discovered a plethora of neutral and ionized molecules in Titan's ionosphere including, surprisingly, anions and negatively charged molecules extending up to 13,800 u q−1. In this Letter, we forward model the Cassini electron spectrometer response function to this unexpected ionospheric component to achieve an increased mass resolving capability for negatively charged species observed at Titan altitudes of 950–1300 km. We report on detections consistently centered between 25.8 and 26.0… Expand
35 Citations

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#### References

SHOWING 1-10 OF 47 REFERENCES
Negative ion chemistry in Titan's upper atmosphere
The Electron Spectrometer (ELS), one of the sensors making up the Cassini Plasma Spectrometer (CAPS) revealed the existence of numerous negative ions in Titan's upper atmosphere. The observations atExpand
The role of ion‐molecule reactions in the growth of heavy ions in Titan's ionosphere
• Chemistry
• 2014
The Ion and Neutral Mass Spectrometer (INMS) and Cassini Plasma Spectrometer (CAPS) have observed Titan's ionospheric composition and structure over several targeted flybys. In this work we study theExpand
Ion chemistry and N-containing molecules in Titan's upper atmosphere
• Chemistry
• 2007
High-energy photons, electrons, and ions initiate ion–neutral chemistry in Titan’s upper atmosphere by ionizing the major neutral species (nitrogen and methane). The Ion and Neutral Mass SpectrometerExpand
Composition and chemistry of Titan's thermosphere and ionosphere
• Chemistry, Medicine
• Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
• 2008
Observations of Titan's ionospheric chemistry indicate that molecular growth starts in the upper atmosphere rather than at lower altitude, and that Benzene (C6H6) is created by ion chemistry at high altitudes and its main photolysis product, the phenyl radical, is at the origin of the formation of aromatic species at higher altitude. Expand
Reactions of Azine Anions with Nitrogen and Oxygen Atoms: Implications for Titan's Upper Atmosphere and Interstellar Chemistry.
• Chemistry, Medicine
• Journal of the American Chemical Society
• 2015
The rich gas-phase chemistry observed in this work provides a better understanding of ion-atom reactions and their contributions to ionospheric chemistry as well as the chemical processing that occurs in the boundary layers between diffuse and dense interstellar clouds. Expand
Reactions of substituted benzene anions with N and O atoms: Chemistry in Titan's upper atmosphere and the interstellar medium.
• Chemistry, Medicine
• The Journal of chemical physics
• 2016
In insight into the rich gas-phase chemistry of aromatic ion-atom reactions and their relevance to ionospheric and interstellar chemistry, spin conversion is found to be critical for understanding some product distributions. Expand
On the amount of heavy molecular ions in Titan's ionosphere
We present observational evidence that the ionosphere of Titan below an altitude of 1150 km is a significant source of heavy (4100 amu) molecular organic species. This study is based on measurementsExpand
ON THE UBIQUITY OF MOLECULAR ANIONS IN THE DENSE INTERSTELLAR MEDIUM
• Physics
• 2013
Results are presented from a survey for molecular anions in seven nearby Galactic star-forming cores and molecular clouds. The hydrocarbon anion C6H- is detected in all seven target sources,Expand
Negative ions at Titan and Enceladus: recent results.
The detection of heavy negative ions in Titan's ionosphere indicates the existence of heavy hydrocarbon and nitrile molecules in this primitive Earth-like atmosphere, and is indicative of a complex balance between neutrals and positively and negatively charged ions. Expand
1D-coupled photochemical model of neutrals, cations and anions in the atmosphere of Titan
Abstract Many models with different characteristics have been published so far to study the chemical processes at work in Titan’s atmosphere. Some models focus on neutral species in the stratosphereExpand