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Role of photoionization in the formation of complex organic molecules in Titan's upper atmosphere
Author(s) -
Imanaka Hiroshi,
Smith Mark A.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl028317
Subject(s) - photoionization , titan (rocket family) , atmosphere of titan , extreme ultraviolet lithography , atmosphere (unit) , mass spectrometry , photochemistry , astrobiology , chemistry , ionization , physics , ion , optics , organic chemistry , meteorology , chromatography
Recent observations by the Cassini Orbiter suggest that complex organic chemistry occurs in the upper atmosphere of Titan. To understand the role of EUV‐VUV light in the complex organic chemistry of Titan's upper atmosphere, we investigate the formation of gaseous species from a N 2 /CH 4 gas mixture as a function of irradiation wavelengths from 50 nm to 150 nm. A N 2 /CH 4 gas mixture (= 95/5) at 0.066 mbar in a windowless photocell is irradiated using a narrowband synchrotron radiation source. The analysis of gaseous products by quadrupole mass spectrometry reveals the formation of heavy organics up to C 7 to C 8 by EUV light irradiation. In particular, the efficient formation of benzene and toluene is observed at wavelengths less than 80 nm, which is well correlated to photoionization of N 2 . In Titan's upper atmosphere, EUV radiation may play an important role in the formation of complex organic molecules through photoionization of N 2 .