Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Direct Measurements of Rate Coefficients for the Reaction of Ethynyl Radical (C2H) With C2H2 at 90 and 120 K Using a Pulsed Laval Apparatus

Published

Author(s)

S Lee, D A. Samuels, R J. Hoobler, S R. Leone

Abstract

Rate coefficients for the reaction C2H + C2H2 -> C4H2 + H are measured at 90 and 120 K by using a new pulsed Laval nozzle apparatus equipped with laser ionization, time-of-flight mass spectrometric detection. The C2H radicals are generated by 193 nm laser photolysis of C2H2, and the reaction product, C4H2 is directly detected by single-photon ionization at 118 nm (10.5 eV). Rate coefficients of (2.7 0.5) X 10-10 and (2.5 0.4) X 10010 cm3 molecule -1s-1 are obtained at 90 and 120 K, compared to the room temperature value of 1.3 x 10010 cmu3^ molecule-1x-1. The results show a significant negative temperature dependence of the reaction rate coefficient below room temperature. The implications for models of planetary atmospheres, such as for Titan, are discussed.
Citation
Journal of Geophysical Research
Volume
105
Issue
No. E6

Keywords

acetylene, rate coefficient, Titan

Citation

Lee, S. , Samuels, D. , Hoobler, R. and Leone, S. (2000), Direct Measurements of Rate Coefficients for the Reaction of Ethynyl Radical (C<sub>2</sub>H) With C<sub>2</sub>H<sub>2</sub> at 90 and 120 K Using a Pulsed Laval Apparatus, Journal of Geophysical Research (Accessed April 12, 2024)
Created May 31, 2000, Updated October 12, 2021