Temperature dependent product yields for the spin forbidden singlet channel of the C(3P) + C2H2 reaction

Abstract

The atomic hydrogen formation channels of the C + C 2 H 2 reaction have been investigated using a continuous supersonic flow reactor over the 52-296 K temperature range. H-atoms were detected directly at 121.567 nm by vacuum ultraviolet laser induced fluorescence.Absolute H-atom yields were determined by comparison with the H-atom signal generated by the C + C 2 H 4 reaction. The product yields agree with earlier crossed beam experiments employing universal detection methods. Incorporating these branching ratios in a gas-grain model of dense interstellar clouds increases the c-C 3 H abundance. This reaction is a minor source of C3-containing molecules in the present simulations.

A combined theoretical and experimental investigation of the kinetics and dynamics of the O(1D) + D2reaction at low temperature

“…The experimental setup has been described in earlier papers, 76,77 while modifications that allowed the kinetics of atom-molecule reactions to be studied are described in more recent work. 16,70,71,75,[78][79][80][81][82][83][84][85][86] In an identical manner to previous investigations of excited state atom reactions, 16,70,71,75,78,81,[84][85][86] only Laval nozzles employing argon were used for these experiments as a result of the fast electronic quenching of O( 1 D) atoms by carrier gases such as N 2 . 75 These Ar based nozzles allowed uniform supersonic flows to be generated at specified temperatures of 50 K, 75 K and 127 K, with calculated densities in the range (1.26-2.59) Â 10 17 cm À3 and flow velocities between 419 and 505 m s À1 .…”

The 12C/13C Ratio in Sgr B2(N): Constraints for Galactic Chemical Evolution and Isotopic Chemistry

“…There are multiple ionmolecule routes to synthesize CH CHCH (Figure 3). These reactions all form carbon-carbon bonds, and have relatively fast rates ranging from 2.2 × 10 −10 to 1.1 × 10 −9 cm 3 s −1 (Wakelam et al 2015;Hickson et al 2016). Two neutral-neutral reactions involving ethene or ethyl radical are also possible pathways, although the branching ratios are not certain (Hickson et al 2016 +  + ( )…”

“…Hickson et al (2016) suggest that the most likely gas-phase route to this molecule is dissociative electron recombination from protonated methylacetylene (allyl cation), CH CHCH 2 2…”

“…Methylacetylene could also be produced on the surface of dust grains by sequential hydrogenation of C 3 . Again, C 3 is first formed in the gas phase, freezing in the 13 C tagging, and is subsequently incorporated onto grain surfaces (Hickson et al 2016). This mechanism, however, could be disrupted by the presence of atomic oxygen on the grain surface.…”

Chemie mit Überschall: 30 Jahre astrochemische Forschung und künftige Herausforderungen

“…Daher standen keinerlei Informationen über Produkte zur Verfügung, außer in einigen besonderen Fällen, bei denen diese ebenfalls mittels LIF nachgewiesen werden konnten. Zum Beispiel führte die Gruppe in Bordeaux vor kurzem mit Blick auf Wasserstoffatome eine Reihe von Messungen der Reaktionen C( 3 P)+NH 3 , C 2 H 2 und H 2 O durch, wobei sie die Reaktion C( 3 P)+C 2 H 4 zur Kalibrierung heranzogen, um die Ausbeute von H‐Atomen als Produkt der erwähnten Reaktionen zu untersuchen . Bei der überwiegenden Mehrheit der Studien konnten jedoch keinerlei quantitative Informationen aus der LIF‐Detektion extrahiert werden, da die Konzentration des Produkts nicht exakt bestimmt werden konnte.…”