Decay Of CH Research Articles

Absolute rate constants for the reactions of CH with O and N atoms

CH(X 2R) was produced by multiple infrared photon dissociation of CH3OH in the presence of excess atomic oxygen or nitrogen. Time-resolved measurements of relative CH concentrations were made at 298 K with a tunable dye laser. Rate constants deduced from the dependence of CH decay rate on atom concentration are (9.5±1.4)×10−11 cm3 s−1 for CH+O and (2.1±.5)×10−11 cm3 s−1 for CH+N.

Absolute rate constant for the CH + O reaction

CH(X 2Π) was produced by multiple infrared photon dissociation of CH 3OH vapour in the presence of excess atomic oxygen. Time-resolved measurements of relative CH concentrations were made at 298 K with a tunable dye laser. From the dependence of CH decay rate on atom concentration, an absolute rate constant (9.4 ± 2)×10 −11 cm 3 molecule −1 s −1 was deduced for the CH + O reaction.

Nanosecond kinetic study of the rotational temperature decay of the CH(A2Δ→X2Π), emission produced by pulse radiolysis of CH4and C2H2

A 10–9 s pulse radiolysis study of the discrete rotational levels of the CH(A2Δ–X2Π) emission gives the kinetics of the rotational temperature decay of CH(A2Δ) during fluorescence; variations of the rate for rotational de-excitation of the discrete levels are determined for ten rotational levels of the (0–0) band. The CH(A2Δ) radical is produced initially from CH4, with 0.07 eV and from C2H2 with 0.6 eV rotational energy. The electronic radiative lifetime has been measured for 3 rotational bands: the values vary from 480 to 575 ns.