Journalartikel

Jahr der Veröffentlichung: 2006

Seiten: 880-885

Zeitschrift: ChemPhysChem

Bandnummer: 7

Heftnummer: 4

ISSN: 1439-4235

DOI Link: https://doi.org/10.1002/cphc.200500555

Verlag: Wiley

Abstract: 
We introduce a novel experimental setup for the generation of carbon atoms by means of pulsed loser ablation with a pulse rate optimized to avoid warming of the matrix. The combination of this technique with annealing of the matrix, recooling, and spectral recording (e.g. IR) allowed us to differentiate between the reactivity of triplet and singlet carbon atoms towards water under matrix-isolation conditions. Our experimental procedure assures the relaxation of all unreacted carbon atoms to their triplet ground state in the 70 K matrix before spectral recording. In agreement with CCSD(T)/cc-pVTZ+ZPVE computational data and earlier lower level results, we find that triplet carbon atoms indeed do not react with water, despite their high initial energy. Intersystem crossing of the triplet to singlet states of hydroxy carbene ore less important, as the barriers for rearrangement initial complex of triplet carbon atoms and water to covalently bound species are too high, and dissociation is more likely. We found no evidence for a direct O-H bond-insertion path for triplet carbon atoms. Self-condensation reactions of triplet carbon atoms ore clearly favored and yield carbon clusters that show reactivity of their own. The proposed formation of aldoses in extraterrestrial environments can therefore only derive from "hot" carbon atoms or through photoreactions.

Harvard-Zitierstil: Schreiner, P. and Reisenauer, H. (2006) The "non-reaction" of ground-state triplet carbon atoms with water revisited, ChemPhysChem, 7(4), pp. 880-885. https://doi.org/10.1002/cphc.200500555

APA-Zitierstil: Schreiner, P., & Reisenauer, H. (2006). The "non-reaction" of ground-state triplet carbon atoms with water revisited. ChemPhysChem. 7(4), 880-885. https://doi.org/10.1002/cphc.200500555