Extraordinary branching ratios in astrophysically important dissociative recombination reactions
2004 (English)In: Faraday discussions (Online), ISSN 1364-5498, E-ISSN 1359-6640, Vol. 127, 425-437 p.Article in journal (Refereed) Published
Branching ratios of the dissociative recombination reactions of the astrophysically relevant ions DCO+, N2H+ and DOCO+ ( as substitute for HOCO+) have been measured using the CRYRING storage ring at the Manne Siegbahn Laboratory at the University of Stockholm, Sweden. For DCO+, the channel leading to D and CO was by far the most important one ( branching ratio 0.88), only small contributions of the CD+O and OD+C product pathways ( branching ratios 0.06 each) were recorded. In the case of N2H+ the surprising result of a break-up of the N-N bond to N and NH ( branching ratio 0.64) was found with the branching ratio of the N-2+H product channel therefore displaying a branching ratio of only 0.36. In the case of DOCO+, the three-body break-up into D+O+CO dominated ( branching ratio 0.68), whereas the contribution of the CO2+H channel was only minute (0.05). The remaining share ( branching ratio 0.27) was taken by the pathway leading to OH+CO. For the dissociative recombination of N2H+ and DOCO+ also absolute reaction cross sections were obtained in the collisional energy range between 0 and 1 eV. From these cross sections it was possible to work out the thermal rate constants, which were found to be k(T) = 1.0 +/- 0.1 x 10(-7) (T/300 K)(-0.51 +/- 0.02) cm(3) s(-1) and k(T) = 1.2 +/- 0.1 x 10(-6) (T/300 K)(-0.64 +/- 0.02) cm(3) s(-1) for N2H+ and DOCO+, respectively.
Place, publisher, year, edition, pages
2004. Vol. 127, 425-437 p.
chemical bond, chemical reaction, collisionally activated dissociation, conference paper, energy absorption, energy transfer, molecular dynamics, molecular interaction, molecular mechanics, reaction analysis
IdentifiersURN: urn:nbn:se:kth:diva-43998DOI: 10.1039/b314005aISI: 000223139400026ScopusID: 2-s2.0-5644265151OAI: oai:DiVA.org:kth-43998DiVA: diva2:449118
QC 201110192011-10-192011-10-192011-10-19Bibliographically approved