15min:

BORIS NIZAMOV AND PAUL J. DAGDIGIAN, Department of Chemistry, The Johns Hopkins University, Baltimore, Md 21218-2685.

Cavity ringdown spectroscopy (CRDS) was used to study room temperature chemical reactions of the methylene amidogen radical (CH₂N). The radical was prepared by 193 nm photolysis of formaldoxime, CH₂NOH CH₂N+OH. CRDS signal from both CH₂N and OH [A--X (1,0) band] was observed in the wavelength region 278-288 nm. By comparison of the OH and CH₂N signals, absorption cross section of the CH₂N was determined. To correct for the loss of OH radical by reaction, the rate constant of the reaction of OH with formaldoxime was measured, k(CH₂NOH+OH)= 2.5*10^-12 molecule cm³ s^-1. Reaction of CH₂N with stable molecules such oxygen, hydrogen and methane could not be observed and only an upper limit of the reaction rate constants, < 1.0 *10^-15 molecule cm³ s^-1, could be derived. Self-recombination was the main removal process for the CH₂N radical under the conditions of our experiment.