On the Insertion Reactions of CH2(ã1A1) in to Some Element-Hydrogen Bonds

Abstract

Absolute values for the removal rates of CH2(ã1A1) by NH3, CH3NH2, CH3OH, HCl, and HF have been determined in the gas phase at low pressures and room temperature. CH2(ã1A1) was generated by pulsed laser photolysis of CH2CO. The measurements were carried out by observing the laser induced fluorescence of 1CH2 after excitation by a pulsed laser as a function of the time delay between the photolysis and analysis pulses. The overall rate constants were found to be 2.4, 2.4, 2.3, 1.6 and 0.13 · 1014 cm3/mol s, respectively. NH2 was shown by LIF detection to be a primary product of the reaction of 1CH2 with NH3. The intersystem crossing channel of 1CH2 was investigated by monitoring the formation of CH2(X̃3B1) with laser magnetic resonance. LMR absorption intensities of 3CH2 resulting from quenching of 1CH2 in the presence and absence of the reactant R were compared under otherwise identical conditions. The branching ratios of quenching versus total removal of 1CH2, turned out to be 0.30, 0.13 and 0.98 for NH3, CH3OH, and HF, respectively.