Absolute Density and Sticking Probability of the CN(X2Σ+) Radicals Produced by the Dissociative Excitation Reaction of BrCN with the Microwave Discharge Flow of Ar

Abstract

The 4-0, 5-1, and 7-2 bands of the A2Πi–X2Σ+ transition of the CN radical produced by the dissociative excitation reaction of BrCN with the microwave discharge flow of Ar were observed by laser induced fluorescence (LIF) spectroscopy. The intensity of the LIF spectrum of the individual transition was evaluated by a spectral simulation analysis, and converted to the absolute value by calibrating against Rayleigh scattering by Ar atoms. The effective lifetime of the A2Πi state was measured to be 2.2(5) µs. The absolute number density of the CN(X2Σ+) radicals in the observation region of LIF was evaluated to be 1.5(3)×1020 m-3. Based on this value, the pumping speed, and the amount of a-CNx:H film deposited, the sticking probability of the CN radicals onto the a-CNx:H films was estimated to be 0.01.