Astronomy and Astrophysics – Astronomy
Scientific paper
May 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011iaus..280p.278o&link_type=abstract
The Molecular Universe, Posters from the proceedings of the 280th Symposium of the International Astronomical Union held in Tole
Astronomy and Astrophysics
Astronomy
Scientific paper
We investigated neutral radical-molecule reactions CO + OH without external energy inputs to investigate possible CO2 formation pathways inside dense molecular clouds, where UV field is relatively weak. OH radicals were produced by dissociating H2O in microwave-induced plasma and cooled down to 100 K before they were codeposited with CO on a cold Al surface at 10-40 K. Reaction products were monitored in-situ by FTIR spectroscopy. We observed the formation of CO2 in the reaction products. Furthermore, formation of trans- and cis-HOCO radicals were also identified. On this basis, we consider CO2 was formed by the following reactions on the cold Al surface:
CO + OH → cis-HOCO → trans-HOCO → CO_2 + H,
which have been proposed for the CO2 formation route in the gas phase. Our results suggest that the above reactions have little or no activation barrier. Conversion factor of CO to CO2 was up to 10 {%} under the present experimental conditions. In addition to CO2 and HOCO radicals, we found that carbonic acid, H2CO3, was formed probably by the following reactions:
HOCO + OH → H_2CO_3
H2CO3 has never been found in molecular clouds. However, if H2CO3 really exists in interstellar ices, it may act as an acid molecule to react with base molecules such as NH3, which results in the formation of NH4+, one of the possible candidates for the unidentified 6.8 μ m band observed toward various astronomical sources. Furthermore, we propose that H2CO3 itself could have a contribution to 6.8 μ m band.
Hama Tetsuya
Kouchi Akira
Oba Yasuhiro
Pirronello Valerio
Watanabe Naoki
No associations
LandOfFree
Neutral radical-molecule reactions CO + OH on cold interstellar ices does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Neutral radical-molecule reactions CO + OH on cold interstellar ices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Neutral radical-molecule reactions CO + OH on cold interstellar ices will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-930211