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Title: A CROSSED MOLECULAR BEAMS STUDY ON THE FORMATION OF THE EXOTIC CYANOETHYNYL RADICAL IN TITAN'S ATMOSPHERE

Abstract

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.

Authors:
;  [1]; ;  [2]; ;  [3];  [4]
  1. Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)
  2. Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 (United States)
  3. Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States)
  4. Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan (China)
Publication Date:
OSTI Identifier:
21319516
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 701; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/701/2/1797; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AEROSOLS; ATMOSPHERES; DECOMPOSITION; ELECTRONIC STRUCTURE; GROUND STATES; HYDROCARBONS; HYDROCYANIC ACID; MOLECULAR BEAMS; MOLECULES; MOON; PHOTOCHEMISTRY; PLANETS; PROPIOLONITRILE; RADICALS

Citation Formats

Gu, X, Kaiser, R I, Mebel, A M, Kislov, V V, Klippenstein, S J, Harding, L B, Liang, M C, and Yung, Y. L. A CROSSED MOLECULAR BEAMS STUDY ON THE FORMATION OF THE EXOTIC CYANOETHYNYL RADICAL IN TITAN'S ATMOSPHERE. United States: N. p., 2009. Web. doi:10.1088/0004-637X/701/2/1797; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Gu, X, Kaiser, R I, Mebel, A M, Kislov, V V, Klippenstein, S J, Harding, L B, Liang, M C, & Yung, Y. L. A CROSSED MOLECULAR BEAMS STUDY ON THE FORMATION OF THE EXOTIC CYANOETHYNYL RADICAL IN TITAN'S ATMOSPHERE. United States. https://doi.org/10.1088/0004-637X/701/2/1797; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Gu, X, Kaiser, R I, Mebel, A M, Kislov, V V, Klippenstein, S J, Harding, L B, Liang, M C, and Yung, Y. L. 2009. "A CROSSED MOLECULAR BEAMS STUDY ON THE FORMATION OF THE EXOTIC CYANOETHYNYL RADICAL IN TITAN'S ATMOSPHERE". United States. https://doi.org/10.1088/0004-637X/701/2/1797; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21319516,
title = {A CROSSED MOLECULAR BEAMS STUDY ON THE FORMATION OF THE EXOTIC CYANOETHYNYL RADICAL IN TITAN'S ATMOSPHERE},
author = {Gu, X and Kaiser, R I and Mebel, A M and Kislov, V V and Klippenstein, S J and Harding, L B and Liang, M C and Yung, Y. L.},
abstractNote = {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.},
doi = {10.1088/0004-637X/701/2/1797; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21319516}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 701,
place = {United States},
year = {Thu Aug 20 00:00:00 EDT 2009},
month = {Thu Aug 20 00:00:00 EDT 2009}
}