Laboratory studies of bimolecular reactions of positive ions in interstellar clouds, in comets, and in planetary atmospheres of reducing composition

1977 ◽  
Vol 33 ◽  
pp. 495 ◽  
Author(s):  
W. T., Jr. Huntress
Keyword(s):  
Planetary Atmospheres ◽  
Laboratory Studies ◽  
Bimolecular Reactions ◽  
Interstellar Clouds ◽  
Positive Ions

Electronic Spectra of the Triacetylene Cation (HC6H+) and Protonated Triacetylene (HC6H2+) Tagged with Ar

2019 ◽  
Vol 72 (4) ◽  
pp. 260 ◽  
Author(s):  
Ugo Jacovella ◽  
Giel Muller ◽  
Katherine J. Catani ◽  
Nastasia I. Bartlett ◽  
Evan J. Bieske
Keyword(s):  
Electronic Spectrum ◽  
Gas Phase ◽  
Band System ◽  
Argon Atom ◽  
Planetary Atmospheres ◽  
Phase Spectrum ◽  
Tandem Mass ◽  
Interstellar Clouds ◽  
Combustion Processes ◽  
First Time

Polyacetylene cations (HC2nH+) play important roles in combustion processes and in the chemistry of planetary atmospheres and interstellar clouds. Here we report the electronic spectrum for the triacetylene cation (HC6H+) recorded over the 300–610nm range by photodissociating mass-selected ions tagged with argon atoms in a tandem mass spectrometer. The spectrum shows three band systems that are assigned to (origin transition 16665cm−1), (origin transition 23916cm−1), and (origin transition 29920cm−1). Although the band system is well known, the and band systems are observed for the first time in the gas phase. In addition, the electronic spectrum of the protonated triacteylene cation tagged with an argon atom (HC6-Ar) is reported, providing the first gas-phase spectrum for this species.

Laboratory studies of isotope exchange in ion-neutral reactions: interstellar implications

1981 ◽  
Vol 303 (1480) ◽  
pp. 535-542 ◽  
Keyword(s):  
Low Temperatures ◽  
Isotope Exchange ◽  
Laboratory Data ◽  
Isotopic Ratios ◽  
Laboratory Studies ◽  
Terrestrial Environment ◽  
Interstellar Clouds ◽  
Ion Molecule Reactions ◽  
Significant Process ◽  
Molecule Interactions

The rare stable isotopes of several elements (e.g. D, 13 C and 15 N) have been detected in several interstellar molecules, and their abundance relative to the more common isotope is often enhanced above that in the solar-terrestrial environment. Important questions to answer are to what extent the isotopic ratios in the molecules are representative of those in the cloud matter as a whole, and whether fractionation of the heavier isotope into the molecules via ion—molecule interactions is a significant process. A laboratory study of isotope exchange in ion-molecule reactions has therefore been carried out, the results of which indicate that fractionation of heavy isotopes can occur very efficiently at low temperatures. Consideration is given in this paper to reactions in which H-D, 12 C - 13 C, 14 N - 15 N and 16 O - 18 O exchange occurs, and it is shown how better estimates of the electron density and the temperature in interstellar clouds have been obtained from these laboratory data.

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