Kinetics and mechanism of the CN + NCO --> NCN + CO reaction studied by experiment and theory.
The rate coefficients for the CN + NCO --> NCN + CO reaction have been measured by a laser-photolysis/laser-induced fluorescence technique in the temperature range of 254-353 K and the He pressures of 123-566 Torr. The CN radical was produced from the photolysis of BrCN at 193 nm, and the NCO radical from the CN + O(2) reaction. The NCN radical was monitored by laser-induced fluorescence with a dye laser at 329.01 nm. The rate constants derived from kinetic modeling, with a negative temperature dependence but no pressure effect, can be expressed by k = (2.15 +/- 0.70) x 10(-11) exp[(155 +/- 92)/T] cm(3) molecule(-1) s(-1), where the quoted errors are two standard deviations. The reaction mechanism and rate constant have also been theoretically predicted for the temperature range of 200-3000 K at He pressures ranging from 10(-4) Torr to 1000 atm based on dual channel Rice-Ramsperger-Kassel-Marcus (RRKM) calculations with the potential energy surface evaluated at the G2M and CCSD(T) levels. The rate constant calculated by variational RRKM theory agrees reasonably with experimental data.
Department of Applied Chemistry and Center for Interdisciplinary Molecular Science, Chiao Tung University, Taiwan 30010.
Shiang-Yang
SY
Tzeng
Po-Hsueh
PH
Chen
Niann S
NS
Wang
L C
LC
Lee
Z F
ZF
Xu
M C
MC
Lin