A crossed molecular beams study on the formation of the exotic cyanoethynyl radical in Titan's atmosphere.
- Chemical Sciences and Engineering Division
The reaction of the dicarbon molecule (C{sub 2}) in its {sup 1}{Sigma}{sub g}{sup +} electronic ground state with hydrogen cyanide HCN(X{sup 1}{Sigma}{sup +}) is investigated in a crossed molecular beam setup to untangle the formation of the cyanoethynyl radical CCCN(X{sup 2}{Sigma}{sup +}) in hydrocarbon-rich atmospheres of planets and their moons such as Titan. Combined with electronic structure and rate theory calculations, we show that this elementary reaction is rapid, has no entrance barriers, and yields CCCN via successive rearrangements of the initial HC{sub 3}N collision complex to the cyanoacetylene intermediate (HCCCN) followed by unimolecular decomposition of the latter without exit barrier. New photochemical models imply that this radical could serve as a key building block to form more complex molecules as observed in situ by the Cassini spacecraft, ultimately leading to organic aerosol particles, which make up the orange-brownish haze layers in Titan's atmosphere.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Aeronautics and Space Administration (NASA)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 1018491
- Report Number(s):
- ANL/CSE/JA-64431; TRN: US201114%%22
- Journal Information:
- Astrophys. J., Vol. 701, Issue Aug. 2009
- Country of Publication:
- United States
- Language:
- ENGLISH
Similar Records
INFRARED SPECTRA AND OPTICAL CONSTANTS OF NITRILE ICES RELEVANT TO TITAN's ATMOSPHERE
Low-temperature formation of polycyclic aromatic hydrocarbons in Titan’s atmosphere