Experimental and theoretical investigation of the UV spectrum and kinetics of the aminomethyl radical, .CH2NH2

Abstract

The aminomethyl radical was produced by the reaction F-. + CH3NH2 --> HF + (CH2NH2)-C-., which was initiated by pulse radiolysis of CH3NH2-SF6 mixtures. The ultraviolet absorption spectrum of CH2NH2 was recorded on a timescale of 2 mu s using a gated optical multichannel analyzer. The vibronic structure observed in the range 270-380 nm was analyzed by comparison with the results Of ab initio calculations. Kinetics of the self-reaction 2(.)CH(2)NH(2) --> products was studied by monitoring the transient absorption of (CH2NH2)-C-. at 319.5 nm. A value of k = 8.1 x 10(-11) cm(3) molecule(-1) s(-1) was derived from the observed second-order kinetics combined with an estimated yield of the radical. In the presence of oxygen the decay rate was found to increase in accordance with the reaction (CH2NH2)-C-. + O-2 --> products proceeding with a rate constant of 7.8(8) x 10(-11) cm(3) molecule(-1) s(-1).